diff --git a/modules/taxonomy/taxonomy.module b/modules/taxonomy/taxonomy.module
index ca77907..ee12be7 100644
--- a/modules/taxonomy/taxonomy.module
+++ b/modules/taxonomy/taxonomy.module
@@ -1906,3 +1906,35 @@ function taxonomy_taxonomy_term_delete($term) {
 /**
  * @} End of "defgroup taxonomy_index".
  */
+
+/**
+ * Implements hook_entity_query_alter().
+ *
+ * Converts EntityFieldQuery instances on taxonomy terms that have an entity
+ * condition on term bundles (vocabulary machine names). Since the vocabulary
+ * machine name is not present in the {taxonomy_term_data} table itself, we have
+ * to convert the bundle condition into a proprety condition of vocabulary IDs
+ * to match against {taxonomy_term_data}.vid.
+ */
+function taxonomy_entity_query_alter($query) {
+  $conditions = &$query->entityConditions;
+
+  // Alter only taxonomy term queries with bundle conditions.
+  if (isset($conditions['entity_type']) && $conditions['entity_type']['value'] == 'taxonomy_term' && isset($conditions['bundle'])) {
+    // Convert vocabulary machine names to vocabulary IDs.
+    $vocabulary_data = taxonomy_vocabulary_get_names();
+    $vids = array();
+    if (is_array($conditions['bundle']['value'])) {
+      foreach ($conditions['bundle']['value'] as $vocabulary_machine_name) {
+        $vids[] = $vocabulary_data[$vocabulary_machine_name]->vid;
+      }
+    }
+    else {
+      $vocabulary_machine_name = $conditions['bundle']['value'];
+      $vids = $vocabulary_data[$vocabulary_machine_name]->vid;
+    }
+
+    $query->propertyCondition('vid', $vids, $conditions['bundle']['operator']);
+    unset($conditions['bundle']);
+  }
+}
diff --git a/modules/taxonomy/taxonomy.test b/modules/taxonomy/taxonomy.test
index 42b4d47..a84962d 100644
--- a/modules/taxonomy/taxonomy.test
+++ b/modules/taxonomy/taxonomy.test
@@ -1879,3 +1879,57 @@ class TaxonomyThemeTestCase extends TaxonomyWebTestCase {
     $this->assertRaw('seven/style.css', t("The administrative theme's CSS appears on the page for editing a taxonomy term."));
   }
 }
+
+/**
+ * Tests the functionality of EntityFieldQuery for taxonomy entities.
+ */
+class TaxonomyEFQTestCase extends TaxonomyWebTestCase {
+  public static function getInfo() {
+    return array(
+      'name' => 'Taxonomy EntityFieldQuery',
+      'description' => 'Verifies operation of a taxonomy-based EntityFieldQuery.',
+      'group' => 'Taxonomy',
+    );
+  }
+
+  function setUp() {
+    parent::setUp();
+    $this->admin_user = $this->drupalCreateUser(array('administer taxonomy'));
+    $this->drupalLogin($this->admin_user);
+    $this->vocabulary = $this->createVocabulary();
+  }
+
+  /**
+   * Tests that a basic taxonomy EntityFieldQuery works.
+   */
+  function testTaxonomyEFQ() {
+    $terms = array();
+    for ($i = 0; $i < 5; $i++) {
+      $term = $this->createTerm($this->vocabulary);
+      $terms[$term->tid] = $term;
+    }
+    $query = new EntityFieldQuery();
+    $query->entityCondition('entity_type', 'taxonomy_term');
+    $result = $query->execute();
+    $result = $result['taxonomy_term'];
+    asort($result);
+    $this->assertEqual(array_keys($terms), array_keys($result), 'Taxonomy terms were retrieved by EntityFieldQuery.');
+
+    // Create a second vocabulary and five more terms.
+    $vocabulary2 = $this->createVocabulary();
+    $terms2 = array();
+    for ($i = 0; $i < 5; $i++) {
+      $term = $this->createTerm($vocabulary2);
+      $terms2[$term->tid] = $term;
+    }
+
+    $query = new EntityFieldQuery();
+    $query->entityCondition('entity_type', 'taxonomy_term');
+    $query->entityCondition('bundle', $vocabulary2->machine_name);
+    $result = $query->execute();
+    $result = $result['taxonomy_term'];
+    asort($result);
+    $this->assertEqual(array_keys($terms2), array_keys($result), format_string('Taxonomy terms from the %name vocabulary were retrieved by EntityFieldQuery.', array('%name' => $vocabulary2->name)));
+  }
+
+}