diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -1541,6 +1541,7 @@
     'PhabricatorClusterConfigOptions' => 'applications/config/option/PhabricatorClusterConfigOptions.php',
     'PhabricatorCommitBranchesField' => 'applications/repository/customfield/PhabricatorCommitBranchesField.php',
     'PhabricatorCommitCustomField' => 'applications/repository/customfield/PhabricatorCommitCustomField.php',
+    'PhabricatorCommitMergedCommitsField' => 'applications/repository/customfield/PhabricatorCommitMergedCommitsField.php',
     'PhabricatorCommitSearchEngine' => 'applications/audit/query/PhabricatorCommitSearchEngine.php',
     'PhabricatorCommitTagsField' => 'applications/repository/customfield/PhabricatorCommitTagsField.php',
     'PhabricatorCommonPasswords' => 'applications/auth/constants/PhabricatorCommonPasswords.php',
@@ -4906,6 +4907,7 @@
     'PhabricatorClusterConfigOptions' => 'PhabricatorApplicationConfigOptions',
     'PhabricatorCommitBranchesField' => 'PhabricatorCommitCustomField',
     'PhabricatorCommitCustomField' => 'PhabricatorCustomField',
+    'PhabricatorCommitMergedCommitsField' => 'PhabricatorCommitCustomField',
     'PhabricatorCommitSearchEngine' => 'PhabricatorApplicationSearchEngine',
     'PhabricatorCommitTagsField' => 'PhabricatorCommitCustomField',
     'PhabricatorCommonPasswords' => 'Phobject',
diff --git a/src/applications/repository/customfield/PhabricatorCommitMergedCommitsField.php b/src/applications/repository/customfield/PhabricatorCommitMergedCommitsField.php
new file mode 100644
--- /dev/null
+++ b/src/applications/repository/customfield/PhabricatorCommitMergedCommitsField.php
@@ -0,0 +1,68 @@
+<?php
+
+final class PhabricatorCommitMergedCommitsField
+  extends PhabricatorCommitCustomField {
+
+  public function getFieldKey() {
+    return 'diffusion:mergedcommits';
+  }
+
+  public function shouldAppearInTransactionMail() {
+    return true;
+  }
+
+  public function updateTransactionMailBody(
+    PhabricatorMetaMTAMailBody $body,
+    PhabricatorApplicationTransactionEditor $editor,
+    array $xactions) {
+
+    // Get all the merged commits if this commit is a merge
+    $merges_caption = '';
+    $limit = 50;
+    $commit = $this->getObject();
+
+    try {
+      $drequest = DiffusionRequest::newFromDictionary(
+        array(
+          'user' => PhabricatorUser::getOmnipotentUser(),
+          'initFromConduit' => false,
+          'repository' => $commit->getRepository(),
+          'commit' => $commit->getCommitIdentifier(),
+        ));
+
+      $merges = DiffusionPathChange::newFromConduit(
+        DiffusionQuery::callConduitWithDiffusionRequest(
+        PhabricatorUser::getOmnipotentUser(),
+        $drequest,
+        'diffusion.mergedcommitsquery',
+        array(
+          'commit' => $commit->getCommitIdentifier(),
+          'limit' => $limit + 1,
+        )));
+
+      if (count($merges) > $limit) {
+        $merges = array_slice($merges, 0, $limit);
+        $merges_caption =
+          "This commit merges more than {$limit} changes. Only the first ".
+          "{$limit} are shown.\n";
+      }
+
+      if ($merges) {
+        for ($i = 0; $i < count($merges); $i++) {
+          $merges[$i] = $merges[$i]->getAuthorName().
+            ': '.
+            $merges[$i]->getSummary();
+        }
+        $body->addTextSection(
+          pht('MERGED COMMITS'),
+          $merges_caption.implode("\n", $merges));
+      }
+
+    } catch (ConduitException $ex) {
+      // Log the exception and continue.
+      phlog($ex);
+    }
+
+  }
+
+}