diff --git a/lib/connection.js b/lib/connection.js
index 8ba8f32b248..670a98426b9 100644
--- a/lib/connection.js
+++ b/lib/connection.js
@@ -1359,7 +1359,7 @@ Connection.prototype.setClient = function setClient(client) {
   if (!(client instanceof mongodb.MongoClient)) {
     throw new MongooseError('Must call `setClient()` with an instance of MongoClient');
   }
-  if (this.client != null || this.readyState !== STATES.disconnected) {
+  if (this.readyState !== STATES.disconnected) {
     throw new MongooseError('Cannot call `setClient()` on a connection that is already connected.');
   }
   if (client.topology == null) {