diff --git a/lib/aggregation_cursor.js b/lib/aggregation_cursor.js
index 8ad940bdd4..9fcae6a64d 100644
--- a/lib/aggregation_cursor.js
+++ b/lib/aggregation_cursor.js
@@ -89,7 +89,9 @@ var AggregationCursor = function(bson, ns, cmd, options, topology, topologyOptio
     // Topology Options
     topologyOptions: topologyOptions,
     // Promise library
-    promiseLibrary: promiseLibrary
+    promiseLibrary: promiseLibrary,
+    // Optional ClientSession
+    session: options.session
   };
 };