diff --git a/types/mongodb/index.d.ts b/types/mongodb/index.d.ts
index 19cf0136e2..32bc523d38 100644
--- a/types/mongodb/index.d.ts
+++ b/types/mongodb/index.d.ts
@@ -5,6 +5,7 @@
 //                 Gady Piazza <https://github.com/kikar>
 //                 Jason Dreyzehner <https://github.com/bitjson>
 //                 Gaurav Lahoti <https://github.com/dante-101>
+//                 Mariano Cortesi <https://github.com/dante-101>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.3
 
@@ -146,6 +147,9 @@ export interface DbCreateOptions {
     promiseLibrary?: Object;
     // https://docs.mongodb.com/manual/reference/read-concern/#read-concern
     readConcern?: { level?: Object };
+    // Sets a cap on how many operations the driver will buffer up before giving up on getting a
+    // working connection, default is -1 which is unlimited.
+    bufferMaxEntries?: number;
 }
 
 // http://mongodb.github.io/node-mongodb-native/2.2/api/Server.html
diff --git a/types/mongodb/mongodb-tests.ts b/types/mongodb/mongodb-tests.ts
index 2b8c49d186..52f2d6e4f8 100644
--- a/types/mongodb/mongodb-tests.ts
+++ b/types/mongodb/mongodb-tests.ts
@@ -3,7 +3,7 @@ import mongodb = require('mongodb');
 var MongoClient = mongodb.MongoClient;
 
 var format  = require('util').format;
-let options = {
+let options: mongodb.MongoClientOptions = {
     authSource           : ' ',
     w                    : 1,
     wtimeout             : 300,