diff --git a/lib/6to5/generation/generators/expressions.js b/lib/6to5/generation/generators/expressions.js
index 7bd7a22bc5..b246abf27f 100644
--- a/lib/6to5/generation/generators/expressions.js
+++ b/lib/6to5/generation/generators/expressions.js
@@ -1,5 +1,6 @@
 var util = require("../../util");
 var t    = require("../../types");
+var _    = require("lodash");
 
 exports.UnaryExpression = function (node, print) {
   var hasSpace = /[a-z]$/.test(node.operator);
@@ -103,7 +104,12 @@ exports.MemberExpression = function (node, print) {
     throw new TypeError("Got a MemberExpression for MemberExpression property");
   }
 
-  if (node.computed) {
+  var computed = node.computed;
+  if (t.isLiteral(node.property) && _.isNumber(node.property.value)) {
+    computed = true;
+  }
+
+  if (computed) {
     this.push("[");
     print(node.property);
     this.push("]");