diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
index adfba5e543..a164adf5aa 100644
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -94,6 +94,7 @@ phutil_register_library_map(array(
     'ConduitAPI_conduit_ping_Method' => 'applications/conduit/method/conduit/ping',
     'ConduitAPI_daemon_launched_Method' => 'applications/conduit/method/daemon/launched',
     'ConduitAPI_daemon_log_Method' => 'applications/conduit/method/daemon/log',
+    'ConduitAPI_differential_createcomment_Method' => 'applications/conduit/method/differential/createcomment',
     'ConduitAPI_differential_creatediff_Method' => 'applications/conduit/method/differential/creatediff',
     'ConduitAPI_differential_createrevision_Method' => 'applications/conduit/method/differential/createrevision',
     'ConduitAPI_differential_find_Method' => 'applications/conduit/method/differential/find',
@@ -819,6 +820,7 @@ phutil_register_library_map(array(
     'ConduitAPI_conduit_ping_Method' => 'ConduitAPIMethod',
     'ConduitAPI_daemon_launched_Method' => 'ConduitAPIMethod',
     'ConduitAPI_daemon_log_Method' => 'ConduitAPIMethod',
+    'ConduitAPI_differential_createcomment_Method' => 'ConduitAPIMethod',
     'ConduitAPI_differential_creatediff_Method' => 'ConduitAPIMethod',
     'ConduitAPI_differential_createrevision_Method' => 'ConduitAPIMethod',
     'ConduitAPI_differential_find_Method' => 'ConduitAPIMethod',
diff --git a/src/applications/conduit/method/differential/createcomment/ConduitAPI_differential_createcomment_Method.php b/src/applications/conduit/method/differential/createcomment/ConduitAPI_differential_createcomment_Method.php
new file mode 100644
index 0000000000..062c76f58b
--- /dev/null
+++ b/src/applications/conduit/method/differential/createcomment/ConduitAPI_differential_createcomment_Method.php
@@ -0,0 +1,70 @@
+<?php
+
+/*
+ * Copyright 2011 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @group conduit
+ */
+class ConduitAPI_differential_createcomment_Method extends ConduitAPIMethod {
+
+  public function getMethodDescription() {
+    return "Add a comment to a Differential revision.";
+  }
+
+  public function defineParamTypes() {
+    return array(
+      'revision_id' => 'required revisionid',
+      'message'     => 'required string',
+    );
+  }
+
+  public function defineReturnType() {
+    return 'nonempty dict';
+  }
+
+  public function defineErrorTypes() {
+    return array(
+      'ERR_BAD_REVISION' => 'Bad revision ID.',
+    );
+  }
+
+  protected function execute(ConduitAPIRequest $request) {
+    $revision = id(new DifferentialRevision())->load(
+      $request->getValue('revision_id'));
+    if (!$revision) {
+      throw new ConduitException('ERR_BAD_REVISION');
+    }
+
+    $content_source = PhabricatorContentSource::newForSource(
+      PhabricatorContentSource::SOURCE_CONDUIT,
+      array());
+
+    $editor = new DifferentialCommentEditor(
+      $revision,
+      $request->getUser()->getPHID(),
+      DifferentialAction::ACTION_COMMENT);
+    $editor->setContentSource($content_source);
+    $editor->setMessage($request->getValue('message'));
+    $editor->save();
+
+    return array(
+      'revisionid'  => $revision->getID(),
+      'uri'         => PhabricatorEnv::getURI('/D'.$revision->getID()),
+    );
+  }
+
+}
diff --git a/src/applications/conduit/method/differential/createcomment/__init__.php b/src/applications/conduit/method/differential/createcomment/__init__.php
new file mode 100644
index 0000000000..921d030721
--- /dev/null
+++ b/src/applications/conduit/method/differential/createcomment/__init__.php
@@ -0,0 +1,20 @@
+<?php
+/**
+ * This file is automatically generated. Lint this module to rebuild it.
+ * @generated
+ */
+
+
+
+phutil_require_module('phabricator', 'applications/conduit/method/base');
+phutil_require_module('phabricator', 'applications/conduit/protocol/exception');
+phutil_require_module('phabricator', 'applications/differential/constants/action');
+phutil_require_module('phabricator', 'applications/differential/editor/comment');
+phutil_require_module('phabricator', 'applications/differential/storage/revision');
+phutil_require_module('phabricator', 'applications/metamta/contentsource/source');
+phutil_require_module('phabricator', 'infrastructure/env');
+
+phutil_require_module('phutil', 'utils');
+
+
+phutil_require_source('ConduitAPI_differential_createcomment_Method.php');