diff -u b/serial.module b/serial.module
--- b/serial.module
+++ b/serial.module
@@ -112,35 +112,57 @@
   }
 }
 
-// Tokens for fields are currently not supported - http://drupal.org/node/691078.
-
-///**
-// * Implements hook_token_info().
-// */
+/**
+ * Implements hook_token_info().
+ *
+ * Here are examples how to use token with serial field:
+ *    node:field-serial-name or user:field-serial-name-2
+ */
 //function serial_token_info() {
-//  $type = array(
-//    'name' => t('Nodes'),
-//    'description' => t('Tokens related to individual nodes.'),
-//    'needs-data' => 'node',
-//  );
-//  $node['serial'] = array(
-//    'name' => t("Serial Field"),
-//    'description' =>  t('Serial field value (unique per node type)'),
-//    'needs-data' => 'node',
-//  );
-//  return array(
-//    'types' => array('node' => $type),
-//    'tokens' => array('node' => $node),
-//  );
-//}
-//
-///**
-// * Implements hook_tokens().
-// */
-//function serial_tokens($type, $tokens, $data, $options) {
-//  // TODO
+//   No need to define new types or tokens.
 //}
 
+/**
+ * Implements hook_tokens().
+ *
+ * Replace token for generic entity type.
+ */
+function serial_tokens($type, $tokens, $data, $options) {
+  $replacements = array();
+  $sanitize = !empty($options['sanitize']);
+
+  $entity_info = entity_get_info($type);
+  // Make sure type is entity type.
+  if (empty($entity_info)) {
+    return $replacements;
+  }
+
+  $entity_type = $type;
+  if (!empty($data[$entity_type])) {
+    // Generic entity.
+    $entity = $data[$entity_type];
+
+    foreach ($tokens as $name => $original) {
+      // Convert token to field name.
+      $field_name = str_replace('-', '_', $name);
+
+      $field_info = field_info_field($field_name);
+      if ($field_info['type'] == 'serial') {
+        $items = field_get_items($entity_type, $entity, $field_name);
+        if (empty($items)) {
+          continue;
+        }
+
+        $item = reset($items);
+        $serial_value = $item['value'];
+        $replacements[$original] = $sanitize ? filter_xss($serial_value) : $serial_value;
+      }
+    }
+  }
+
+  return $replacements;
+}
+
 //=================//
 // Field Formatter //
 //=================//