diff --git a/date_popup/date_popup.module b/date_popup/date_popup.module
index b7f2b4b..aa460f5 100644
--- a/date_popup/date_popup.module
+++ b/date_popup/date_popup.module
@@ -554,7 +554,9 @@ function date_popup_process_time_part(&$element) {
  * contains a string, after submission it contains an array.
  */
 function date_popup_validate($element, &$form_state) {
-  if (date_hidden_element($element)) {
+  // Disabled and hidden elements won't have any input and don't need
+  // validation.
+  if (date_hidden_element($element) || !empty($element['#disabled'])) {
     return;
   }
 
diff --git a/tests/date_field.test b/tests/date_field.test
index 335bb8a..9ea0f11 100644
--- a/tests/date_field.test
+++ b/tests/date_field.test
@@ -395,3 +395,93 @@ class DateFieldTestCase extends DateFieldBasic {
   }
 
 }
+
+/**
+ * Tests date fields when the form is altered by another module.
+ */
+class DateFormAlterTestCase extends DateFieldBasic {
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Date form alters',
+      'description' => 'Tests date fields when the form is altered by another module.',
+      'group' => 'Date',
+    );
+  }
+
+  public function setUp() {
+    parent::setUp(array('date_test'));
+  }
+
+  /**
+   * Tests that disabled date elements are submitted correctly.
+   */
+  public function testDisabled() {
+    // Create a date fields with simple values for each field type and widget.
+    $parameters = array(
+      'field_type' => array('date', 'datestamp', 'datetime'),
+      'widget_type' => array('date_select', 'date_popup', 'date_text'),
+    );
+    foreach ($this->generatePermutations($parameters) as $p) {
+      $field_name = 'field_test_disabled';
+      $id = 'edit-field-test-disabled';
+      $label = 'Test';
+      $options = array(
+        'label' => $label,
+        'widget_type' => $p['widget_type'],
+        'field_name' => $field_name,
+        'field_type' => $p['field_type'],
+        'input_format' => 'm/d/Y - H:i',
+        'default_format' => 'short'
+      );
+      $this->createDateField($options);
+
+      // Save a node with the API.
+      $node = new stdClass();
+      $node->type = 'story';
+      $node->title = $this->randomName();
+      $node->{$field_name}['und'][0]['value'] =date('Y-m-d h:i:s');
+      node_save($node);
+
+      // Try editing both the existing node and a new node.
+      foreach (array("node/{$node->nid}/edit", 'node/add/story') as $path) {
+        $this->drupalGet($path);
+
+        // Ensure that elements within the field div are rendered as disabled.
+        $this->assertFieldByXpath(
+          "//div[@id='$id']",
+          NULL,
+          "$id div is displayed."
+        );
+        $this->assertFieldByXpath(
+          "//div[@id='$id']//input[@disabled='disabled']|//div[@id='$id']//select[@disabled='disabled']",
+          NULL,
+          "There is a disabled select or input for $id."
+        );
+        // Ensure that no elements within the field div are not disabled.
+        $this->assertNoFieldByXpath(
+          "//div[@id='$id']//input[not(@disabled)]",
+          NULL,
+          "No child input of $id is not disabled."
+        );
+        $this->assertNoFieldByXpath(
+          "//div[@id='$id']//select[not(@disabled)]",
+          NULL,
+          "No child select of $id is not disabled."
+        );
+
+        // Add title value and submit the form.
+        $title = 'Turn around, bright eyes';
+        $edit = array('title' => $title);
+        $this->drupalPost(NULL, $edit, t('Save'));
+
+        // Verify that the form was submitted correctly and that the default
+        // date is displayed.
+        $this->assertText("Story $title has been");
+        $this->assertText(date('m/d/Y'));
+      }
+      $this->deleteDateField($label);
+    }
+  }
+
+}
diff --git a/tests/date_test/date_test.module b/tests/date_test/date_test.module
index 72842b5..eba347e 100644
--- a/tests/date_test/date_test.module
+++ b/tests/date_test/date_test.module
@@ -38,3 +38,12 @@ function date_test_sample_form($form, &$form_state) {
 
   return $form;
 }
+
+/**
+ * Implements hook_form_FORM_ID_alter() for story node forms.
+ *
+ * @see DateFieldTestCase::testDisabled()
+ */
+function date_test_form_story_node_form_alter(&$form, &$form_state) {
+  $form['field_test_disabled']['#disabled'] = TRUE;
+}