diff --git a/ob-elixir.el b/ob-elixir.el
index c6044d0..00645a1 100644
--- a/ob-elixir.el
+++ b/ob-elixir.el
@@ -90,6 +90,33 @@ Matches both regular prompt `iex(N)> ' and continuation `...(N)> '.")
 (defvar ob-elixir--sessions (make-hash-table :test 'equal)
   "Hash table mapping session names to buffer names.")
 
+;;; Mix Dependencies Configuration
+
+(defcustom ob-elixir-mix-command "mix"
+  "Command to run Mix."
+  :type 'string
+  :group 'ob-elixir
+  :safe #'stringp)
+
+(defcustom ob-elixir-deps-cache-dir
+  (expand-file-name "ob-elixir" (or (getenv "XDG_CACHE_HOME") "~/.cache"))
+  "Directory for caching temporary Mix projects.
+
+Each unique set of dependencies gets its own subdirectory,
+named by the hash of the dependencies."
+  :type 'directory
+  :group 'ob-elixir)
+
+(defvar ob-elixir--deps-projects (make-hash-table :test 'equal)
+  "Hash table mapping deps-hash to project directory path.")
+
+(defvar ob-elixir--session-deps (make-hash-table :test 'equal)
+  "Hash table mapping session names to their deps-hash.
+Used to ensure session deps consistency.")
+
+(defvar ob-elixir--cleanup-registered nil
+  "Whether the cleanup hook has been registered.")
+
 ;;; Header Arguments
 
 (defvar org-babel-default-header-args:elixir
@@ -385,6 +412,156 @@ Each statement has the form: var_name = value"
                (ob-elixir--elisp-to-elixir value))))
    (org-babel--get-vars params)))
 
+;;; Deps Block Parsing
+
+(defconst ob-elixir--deps-block-regexp
+  "^[ \t]*#\\+BEGIN_DEPS[ \t]+elixir[ \t]*\n\\(\\(?:.*\n\\)*?\\)[ \t]*#\\+END_DEPS"
+  "Regexp matching a deps block.
+Group 1 captures the deps content.")
+
+(defun ob-elixir--find-deps-for-position (pos)
+  "Find the most recent deps block before POS.
+
+Returns the deps content as a string, or nil if no deps block found."
+  (save-excursion
+    (goto-char pos)
+    (let ((found nil))
+      ;; Search backward for deps blocks
+      (while (and (not found)
+                  (re-search-backward ob-elixir--deps-block-regexp nil t))
+        (when (< (match-end 0) pos)
+          (setq found (match-string-no-properties 1))))
+      found)))
+
+(defun ob-elixir--normalize-deps (deps-string)
+  "Normalize DEPS-STRING for consistent hashing.
+
+Removes comments, extra whitespace, and normalizes formatting."
+  (let ((normalized deps-string))
+    ;; Remove Elixir comments
+    (setq normalized (replace-regexp-in-string "#.*$" "" normalized))
+    ;; Normalize whitespace
+    (setq normalized (replace-regexp-in-string "[ \t\n]+" " " normalized))
+    ;; Trim
+    (string-trim normalized)))
+
+(defun ob-elixir--hash-deps (deps-string)
+  "Compute SHA256 hash of DEPS-STRING for caching."
+  (secure-hash 'sha256 (ob-elixir--normalize-deps deps-string)))
+
+;;; Temporary Mix Project Management
+
+(defconst ob-elixir--mix-exs-template
+  "defmodule ObElixirTemp.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :ob_elixir_temp,
+      version: \"0.1.0\",
+      elixir: \"~> 1.14\",
+      start_permanent: false,
+      deps: deps()
+    ]
+  end
+
+  def application do
+    [extra_applications: [:logger]]
+  end
+
+  defp deps do
+    %s
+  end
+end
+"
+  "Template for temporary Mix project mix.exs file.
+%s is replaced with the deps list.")
+
+(defun ob-elixir--ensure-cache-dir ()
+  "Ensure the cache directory exists."
+  (unless (file-directory-p ob-elixir-deps-cache-dir)
+    (make-directory ob-elixir-deps-cache-dir t)))
+
+(defun ob-elixir--get-deps-project (deps-string)
+  "Get or create a Mix project for DEPS-STRING.
+
+Returns the project directory path, creating and initializing
+the project if necessary."
+  (let* ((deps-hash (ob-elixir--hash-deps deps-string))
+         (cached (gethash deps-hash ob-elixir--deps-projects)))
+    (if (and cached (file-directory-p cached))
+        cached
+      ;; Create new project
+      (ob-elixir--create-deps-project deps-hash deps-string))))
+
+(defun ob-elixir--create-deps-project (deps-hash deps-string)
+  "Create a new temporary Mix project for DEPS-STRING.
+
+DEPS-HASH is used as the directory name.
+Returns the project directory path."
+  (ob-elixir--ensure-cache-dir)
+  (ob-elixir--register-cleanup)
+  
+  (let* ((project-dir (expand-file-name deps-hash ob-elixir-deps-cache-dir))
+         (mix-exs-path (expand-file-name "mix.exs" project-dir))
+         (lib-dir (expand-file-name "lib" project-dir)))
+    
+    ;; Create project structure
+    (make-directory project-dir t)
+    (make-directory lib-dir t)
+    
+    ;; Write mix.exs
+    (with-temp-file mix-exs-path
+      (insert (format ob-elixir--mix-exs-template deps-string)))
+    
+    ;; Write a placeholder module
+    (with-temp-file (expand-file-name "ob_elixir_temp.ex" lib-dir)
+      (insert "defmodule ObElixirTemp do\nend\n"))
+    
+    ;; Fetch dependencies
+    (let ((default-directory project-dir))
+      (message "ob-elixir: Fetching dependencies...")
+      (let ((output (shell-command-to-string
+                     (format "%s deps.get 2>&1" ob-elixir-mix-command))))
+        (when (string-match-p "\\*\\*.*error\\|Could not" output)
+          (error "ob-elixir: Failed to fetch dependencies:\n%s" output)))
+      
+      ;; Compile
+      (message "ob-elixir: Compiling dependencies...")
+      (let ((output (shell-command-to-string
+                     (format "%s compile 2>&1" ob-elixir-mix-command))))
+        (when (string-match-p "\\*\\*.*[Ee]rror" output)
+          (error "ob-elixir: Failed to compile dependencies:\n%s" output))))
+    
+    ;; Cache and return
+    (puthash deps-hash project-dir ob-elixir--deps-projects)
+    (message "ob-elixir: Dependencies ready")
+    project-dir))
+
+;;; Execution with Dependencies
+
+(defun ob-elixir--execute-with-deps (body result-type deps-string)
+  "Execute BODY with dependencies from DEPS-STRING.
+
+RESULT-TYPE is `value' or `output'."
+  (let* ((project-dir (ob-elixir--get-deps-project deps-string))
+         (default-directory project-dir)
+         (tmp-file (org-babel-temp-file "ob-elixir-" ".exs"))
+         (code (if (eq result-type 'value)
+                   (ob-elixir--wrap-for-value body)
+                 body)))
+    
+    ;; Write code to temp file
+    (with-temp-file tmp-file
+      (insert code))
+    
+    ;; Execute with mix run
+    (let ((command (format "%s run --no-compile %s 2>&1"
+                           ob-elixir-mix-command
+                           (shell-quote-argument tmp-file))))
+      (ob-elixir--process-result
+       (shell-command-to-string command)))))
+
 ;;; Session Management
 
 (defun org-babel-elixir-initiate-session (&optional session params)
@@ -583,6 +760,114 @@ Sends variable assignments to the session."
              (ob-elixir-kill-session name))
            ob-elixir--sessions))
 
+;;; Session with Dependencies
+
+(defun ob-elixir--start-session-with-deps (buffer-name session-name deps-string)
+  "Start a new IEx session with dependencies in BUFFER-NAME.
+
+SESSION-NAME is used for the process name.
+DEPS-STRING contains the dependencies specification."
+  (let* ((project-dir (ob-elixir--get-deps-project deps-string))
+         (buffer (get-buffer-create buffer-name))
+         (default-directory project-dir)
+         (process-environment (cons "TERM=dumb" process-environment)))
+    
+    (with-current-buffer buffer
+      ;; Start IEx with Mix project
+      (make-comint-in-buffer
+       (format "ob-elixir-%s" session-name)
+       buffer
+       ob-elixir-iex-command
+       nil
+       "-S" "mix")
+      
+      ;; Wait for initial prompt (longer timeout for deps loading)
+      (ob-elixir--wait-for-prompt buffer 30)
+      
+      ;; Configure IEx for programmatic use
+      (ob-elixir--configure-session buffer)
+      
+      buffer)))
+
+(defun ob-elixir--get-or-create-session-with-deps (name deps-string)
+  "Get or create an IEx session NAME with DEPS-STRING."
+  (let* ((deps-hash (ob-elixir--hash-deps deps-string))
+         (buffer-name (format "*ob-elixir:%s*" name))
+         (existing (get-buffer buffer-name))
+         (existing-deps (gethash name ob-elixir--session-deps)))
+    
+    ;; Check if existing session has different deps
+    (when (and existing existing-deps (not (string= existing-deps deps-hash)))
+      (message "ob-elixir: Session %s has different deps, recreating..." name)
+      (ob-elixir-kill-session name)
+      (setq existing nil))
+    
+    (if (and existing (org-babel-comint-buffer-livep existing))
+        existing
+      ;; Create new session
+      (let ((buffer (ob-elixir--start-session-with-deps buffer-name name deps-string)))
+        (puthash name (buffer-name buffer) ob-elixir--sessions)
+        (puthash name deps-hash ob-elixir--session-deps)
+        buffer))))
+
+(defun ob-elixir--evaluate-in-session-with-deps (session body result-type deps-string)
+  "Evaluate BODY in SESSION with DEPS-STRING context.
+
+RESULT-TYPE is `value' or `output'."
+  (let* ((buffer (ob-elixir--get-or-create-session-with-deps session deps-string))
+         (code (if (eq result-type 'value)
+                   (ob-elixir--session-wrap-for-value body)
+                 body))
+         (eoe-indicator ob-elixir--eoe-marker)
+         (full-body (concat code "\nIO.puts(\"" eoe-indicator "\")"))
+         output)
+    
+    (unless buffer
+      (error "Failed to create Elixir session with deps: %s" session))
+    
+    (setq output
+          (org-babel-comint-with-output
+              (buffer eoe-indicator t full-body)
+            (ob-elixir--send-command buffer full-body)))
+    
+    (ob-elixir--clean-session-output output result-type)))
+
+;;; Deps Project Cleanup
+
+(defun ob-elixir--register-cleanup ()
+  "Register cleanup hook if not already registered."
+  (unless ob-elixir--cleanup-registered
+    (add-hook 'kill-emacs-hook #'ob-elixir-cleanup-deps-projects)
+    (setq ob-elixir--cleanup-registered t)))
+
+(defun ob-elixir-cleanup-deps-projects ()
+  "Delete all temporary Mix projects created by ob-elixir.
+
+Called automatically on Emacs exit."
+  (interactive)
+  (maphash
+   (lambda (_hash project-dir)
+     (when (and project-dir (file-directory-p project-dir))
+       (condition-case err
+           (delete-directory project-dir t)
+         (error
+          (message "ob-elixir: Failed to delete %s: %s" project-dir err)))))
+   ob-elixir--deps-projects)
+  (clrhash ob-elixir--deps-projects)
+  (message "ob-elixir: Cleaned up temporary Mix projects"))
+
+(defun ob-elixir-list-deps-projects ()
+  "List all cached dependency projects."
+  (interactive)
+  (if (= (hash-table-count ob-elixir--deps-projects) 0)
+      (message "No cached dependency projects")
+    (with-output-to-temp-buffer "*ob-elixir deps projects*"
+      (princ "Cached ob-elixir dependency projects:\n\n")
+      (maphash
+       (lambda (hash dir)
+         (princ (format "  %s\n    -> %s\n" (substring hash 0 12) dir)))
+       ob-elixir--deps-projects))))
+
 ;;; Execution
 
 (defconst ob-elixir--value-wrapper
@@ -634,15 +919,26 @@ This function is called by `org-babel-execute-src-block'."
   (let* ((session (cdr (assq :session params)))
          (result-type (cdr (assq :result-type params)))
          (result-params (cdr (assq :result-params params)))
+         ;; Find deps for this block's position
+         (deps-string (ob-elixir--find-deps-for-position (point)))
          ;; Expand body with variable assignments
          (full-body (org-babel-expand-body:generic
                      body params
                      (org-babel-variable-assignments:elixir params)))
-         (result (if (and session (not (string= session "none")))
-                     ;; Session mode
-                     (ob-elixir--evaluate-in-session session full-body result-type)
-                   ;; External process mode
-                   (ob-elixir--execute full-body result-type))))
+         (result (cond
+                  ;; Session mode with deps
+                  ((and session (not (string= session "none")) deps-string)
+                   (ob-elixir--evaluate-in-session-with-deps
+                    session full-body result-type deps-string))
+                  ;; Session mode without deps
+                  ((and session (not (string= session "none")))
+                   (ob-elixir--evaluate-in-session session full-body result-type))
+                  ;; Non-session with deps
+                  (deps-string
+                   (ob-elixir--execute-with-deps full-body result-type deps-string))
+                  ;; Plain execution
+                  (t
+                   (ob-elixir--execute full-body result-type)))))
     (org-babel-reassemble-table
      (org-babel-result-cond result-params
        ;; For output/scalar/verbatim - return as-is
diff --git a/test/test-ob-elixir-deps.el b/test/test-ob-elixir-deps.el
new file mode 100644
index 0000000..80c52fd
--- /dev/null
+++ b/test/test-ob-elixir-deps.el
@@ -0,0 +1,213 @@
+;;; test-ob-elixir-deps.el --- Deps block tests -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2024 Your Name
+
+;; Author: Your Name <your.email@example.com>
+
+;; This file is not part of GNU Emacs.
+
+;;; Commentary:
+
+;; Tests for ob-elixir Mix dependencies support.
+
+;;; Code:
+
+(require 'ert)
+(require 'ob-elixir)
+
+;;; Parsing Tests
+
+(ert-deftest ob-elixir-test-deps-block-parsing ()
+  "Test finding deps blocks in buffer."
+  (with-temp-buffer
+    (insert "#+BEGIN_DEPS elixir\n[{:jason, \"~> 1.4\"}]\n#+END_DEPS\n\n")
+    (insert "#+BEGIN_SRC elixir\nJason.encode!(%{})\n#+END_SRC\n")
+    (goto-char (point-max))
+    (let ((deps (ob-elixir--find-deps-for-position (point))))
+      (should deps)
+      (should (string-match-p ":jason" deps)))))
+
+(ert-deftest ob-elixir-test-deps-block-override ()
+  "Test that later deps blocks override earlier ones."
+  (with-temp-buffer
+    (insert "#+BEGIN_DEPS elixir\n[{:jason, \"~> 1.4\"}]\n#+END_DEPS\n\n")
+    (insert "#+BEGIN_SRC elixir\ncode1\n#+END_SRC\n\n")
+    (insert "#+BEGIN_DEPS elixir\n[{:httpoison, \"~> 2.0\"}]\n#+END_DEPS\n\n")
+    (let ((pos (point)))
+      (insert "#+BEGIN_SRC elixir\ncode2\n#+END_SRC\n")
+      (let ((deps (ob-elixir--find-deps-for-position (+ pos 10))))
+        (should deps)
+        (should (string-match-p ":httpoison" deps))
+        (should-not (string-match-p ":jason" deps))))))
+
+(ert-deftest ob-elixir-test-no-deps-block ()
+  "Test behavior when no deps block exists."
+  (with-temp-buffer
+    (insert "#+BEGIN_SRC elixir\n1 + 1\n#+END_SRC\n")
+    (should (null (ob-elixir--find-deps-for-position (point))))))
+
+(ert-deftest ob-elixir-test-deps-block-before-position ()
+  "Test that deps block must be before the position."
+  (with-temp-buffer
+    (insert "#+BEGIN_SRC elixir\n1 + 1\n#+END_SRC\n\n")
+    (let ((pos (point)))
+      (insert "#+BEGIN_DEPS elixir\n[{:jason, \"~> 1.4\"}]\n#+END_DEPS\n")
+      ;; Position is before deps block, should not find it
+      (should (null (ob-elixir--find-deps-for-position pos))))))
+
+(ert-deftest ob-elixir-test-deps-hash-consistency ()
+  "Test that same deps produce same hash."
+  (let ((deps1 "[{:jason, \"~> 1.4\"}]")
+        (deps2 "[{:jason,   \"~> 1.4\"}]")  ; extra space
+        (deps3 "[{:httpoison, \"~> 2.0\"}]"))
+    (should (string= (ob-elixir--hash-deps deps1)
+                     (ob-elixir--hash-deps deps2)))
+    (should-not (string= (ob-elixir--hash-deps deps1)
+                         (ob-elixir--hash-deps deps3)))))
+
+(ert-deftest ob-elixir-test-normalize-deps ()
+  "Test deps normalization."
+  ;; Extra spaces between tokens get normalized to single space
+  (should (string= (ob-elixir--normalize-deps "[{:a,   \"1\"}]")
+                   (ob-elixir--normalize-deps "[{:a, \"1\"}]")))
+  ;; Comments are stripped
+  (should (string= (ob-elixir--normalize-deps "[{:a, \"1\"}] # comment")
+                   (ob-elixir--normalize-deps "[{:a, \"1\"}]"))))
+
+(ert-deftest ob-elixir-test-normalize-deps-multiline ()
+  "Test normalization of multiline deps."
+  ;; Multiline deps with same content should produce the same hash
+  (let ((multiline1 "[\n  {:jason, \"~> 1.4\"},\n  {:decimal, \"~> 2.0\"}\n]")
+        (multiline2 "[\n{:jason, \"~> 1.4\"},\n{:decimal, \"~> 2.0\"}\n]"))
+    ;; Both should hash to the same value since they have equivalent whitespace normalization
+    (should (string= (ob-elixir--hash-deps multiline1)
+                     (ob-elixir--hash-deps multiline2)))))
+
+(ert-deftest ob-elixir-test-deps-block-with-comments ()
+  "Test deps block parsing with Elixir comments."
+  (with-temp-buffer
+    (insert "#+BEGIN_DEPS elixir\n")
+    (insert "[\n")
+    (insert "  # JSON library\n")
+    (insert "  {:jason, \"~> 1.4\"}\n")
+    (insert "]\n")
+    (insert "#+END_DEPS\n\n")
+    (insert "#+BEGIN_SRC elixir\ncode\n#+END_SRC\n")
+    (goto-char (point-max))
+    (let ((deps (ob-elixir--find-deps-for-position (point))))
+      (should deps)
+      (should (string-match-p ":jason" deps)))))
+
+;;; Mix Project Template Tests
+
+(ert-deftest ob-elixir-test-mix-exs-template ()
+  "Test that mix.exs template is valid."
+  (should (stringp ob-elixir--mix-exs-template))
+  (should (string-match-p "defmodule" ob-elixir--mix-exs-template))
+  (should (string-match-p "use Mix.Project" ob-elixir--mix-exs-template))
+  (should (string-match-p "deps()" ob-elixir--mix-exs-template))
+  (should (string-match-p "%s" ob-elixir--mix-exs-template)))
+
+(ert-deftest ob-elixir-test-mix-exs-generation ()
+  "Test generating mix.exs content."
+  (let ((deps "[{:jason, \"~> 1.4\"}]")
+        (mix-exs (format ob-elixir--mix-exs-template "[{:jason, \"~> 1.4\"}]")))
+    (should (string-match-p ":jason" mix-exs))
+    (should (string-match-p "~> 1.4" mix-exs))))
+
+;;; Cache Directory Tests
+
+(ert-deftest ob-elixir-test-cache-dir-default ()
+  "Test default cache directory."
+  (should (stringp ob-elixir-deps-cache-dir))
+  (should (string-match-p "ob-elixir" ob-elixir-deps-cache-dir)))
+
+;;; Integration Tests (require network and mix)
+
+(ert-deftest ob-elixir-test-deps-project-creation ()
+  "Test creating a temporary Mix project with deps."
+  :tags '(:integration :network)
+  (skip-unless (and (executable-find "mix")
+                    (executable-find "elixir")))
+  (let ((ob-elixir-deps-cache-dir (make-temp-file "ob-elixir-test-" t))
+        (deps "[{:jason, \"~> 1.4\"}]"))
+    (unwind-protect
+        (let ((project-dir (ob-elixir--get-deps-project deps)))
+          (should (file-directory-p project-dir))
+          (should (file-exists-p (expand-file-name "mix.exs" project-dir)))
+          (should (file-directory-p (expand-file-name "deps/jason" project-dir))))
+      ;; Cleanup
+      (ob-elixir-cleanup-deps-projects)
+      (when (file-directory-p ob-elixir-deps-cache-dir)
+        (delete-directory ob-elixir-deps-cache-dir t)))))
+
+(ert-deftest ob-elixir-test-deps-execution ()
+  "Test executing code with deps."
+  :tags '(:integration :network)
+  (skip-unless (and (executable-find "mix")
+                    (executable-find "elixir")))
+  (let ((ob-elixir-deps-cache-dir (make-temp-file "ob-elixir-test-" t))
+        (deps "[{:jason, \"~> 1.4\"}]"))
+    (unwind-protect
+        (let ((result (ob-elixir--execute-with-deps
+                       "Jason.encode!(%{a: 1})"
+                       'value
+                       deps)))
+          ;; Result should contain JSON output with key "a"
+          ;; Jason.encode! returns "{\"a\":1}" which when inspected becomes "\"{\\\"a\\\":1}\""
+          (should (string-match-p "a" result)))
+      ;; Cleanup
+      (ob-elixir-cleanup-deps-projects)
+      (when (file-directory-p ob-elixir-deps-cache-dir)
+        (delete-directory ob-elixir-deps-cache-dir t)))))
+
+(ert-deftest ob-elixir-test-deps-caching ()
+  "Test that deps projects are cached and reused."
+  :tags '(:integration :network)
+  (skip-unless (executable-find "mix"))
+  (let ((ob-elixir-deps-cache-dir (make-temp-file "ob-elixir-test-" t))
+        (deps "[{:jason, \"~> 1.4\"}]"))
+    (unwind-protect
+        (let ((project1 (ob-elixir--get-deps-project deps))
+              (project2 (ob-elixir--get-deps-project deps)))
+          ;; Should return same directory
+          (should (string= project1 project2))
+          ;; Should only have one entry in hash table
+          (should (= 1 (hash-table-count ob-elixir--deps-projects))))
+      ;; Cleanup
+      (ob-elixir-cleanup-deps-projects)
+      (when (file-directory-p ob-elixir-deps-cache-dir)
+        (delete-directory ob-elixir-deps-cache-dir t)))))
+
+(ert-deftest ob-elixir-test-different-deps-different-projects ()
+  "Test that different deps create different projects."
+  :tags '(:integration :network)
+  (skip-unless (executable-find "mix"))
+  (let ((ob-elixir-deps-cache-dir (make-temp-file "ob-elixir-test-" t))
+        (deps1 "[{:jason, \"~> 1.4\"}]")
+        (deps2 "[{:decimal, \"~> 2.0\"}]"))
+    (unwind-protect
+        (let ((project1 (ob-elixir--get-deps-project deps1))
+              (project2 (ob-elixir--get-deps-project deps2)))
+          ;; Should be different directories
+          (should-not (string= project1 project2))
+          ;; Should have two entries in hash table
+          (should (= 2 (hash-table-count ob-elixir--deps-projects))))
+      ;; Cleanup
+      (ob-elixir-cleanup-deps-projects)
+      (when (file-directory-p ob-elixir-deps-cache-dir)
+        (delete-directory ob-elixir-deps-cache-dir t)))))
+
+;;; Cleanup Tests
+
+(ert-deftest ob-elixir-test-cleanup-clears-hash-table ()
+  "Test that cleanup clears the hash table."
+  (let ((ob-elixir--deps-projects (make-hash-table :test 'equal)))
+    (puthash "test-hash" "/tmp/test-dir" ob-elixir--deps-projects)
+    (should (= 1 (hash-table-count ob-elixir--deps-projects)))
+    ;; Cleanup should clear the table (dir doesn't exist, so no error)
+    (ob-elixir-cleanup-deps-projects)
+    (should (= 0 (hash-table-count ob-elixir--deps-projects)))))
+
+(provide 'test-ob-elixir-deps)
+;;; test-ob-elixir-deps.el ends here