diff --git a/src/util/MongoInstance.js b/src/util/MongoInstance.js
index efa209302..20287edb6 100644
--- a/src/util/MongoInstance.js
+++ b/src/util/MongoInstance.js
@@ -77,6 +77,7 @@ export default class MongodbInstance {
     if (storageEngine) result.push('--storageEngine', storageEngine);
     if (dbPath) result.push('--dbpath', dbPath);
     if (!auth) result.push('--noauth');
+    else if (auth) result.push('--auth');
     if (replSet) result.push('--replSet', replSet);
 
     return result.concat(args || []);
diff --git a/src/util/__tests__/MongoInstance-test.js b/src/util/__tests__/MongoInstance-test.js
index d74209c25..c8a5545d7 100644
--- a/src/util/__tests__/MongoInstance-test.js
+++ b/src/util/__tests__/MongoInstance-test.js
@@ -73,6 +73,7 @@ describe('MongoInstance', () => {
       '27555',
       '--dbpath',
       '/data',
+      '--auth',
     ]);
   });