diff --git a/lib/main.js b/lib/main.js
index 852c876b..b67930c5 100644
--- a/lib/main.js
+++ b/lib/main.js
@@ -330,6 +330,7 @@ Lambda.prototype._uploadExisting = function (lambda, params, cb) {
       'MemorySize': params.MemorySize,
       'Role': params.Role,
       'Timeout': params.Timeout,
+      'Runtime': params.Runtime,
       'VpcConfig': params.VpcConfig,
       'Environment': params.Environment
     }, function (err, data) {