diff --git a/lib/Pool.js b/lib/Pool.js
index 251628f70..96446ca36 100644
--- a/lib/Pool.js
+++ b/lib/Pool.js
@@ -127,11 +127,18 @@ Pool.prototype.query = function (sql, values, cb) {
   }
 
   this.getConnection(function (err, conn) {
-    if (err) return cb(err);
+    if (err) {
+      if (typeof cb === 'function') {
+        cb(err);
+      }
+      return;
+    }
 
     conn.query(sql, values, function () {
       conn.release();
-      cb.apply(this, arguments);
+      if (typeof cb === 'function') {
+        cb.apply(this, arguments);
+      }
     });
   });
 };