diff --git a/lib/buffer.js b/lib/buffer.js
index f8ab2b22282338..a24bdd0e006f9f 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -120,7 +120,7 @@ function fromString(string, encoding) {
 function fromArrayLike(obj) {
   const length = obj.length;
   const b = allocate(length);
-  for (let i = 0; i < length; i++)
+  for (var i = 0; i < length; i++)
     b[i] = obj[i] & 255;
   return b;
 }
@@ -208,6 +208,7 @@ Buffer.isEncoding = function(encoding) {
 
 
 Buffer.concat = function(list, length) {
+  var i;
   if (!Array.isArray(list))
     throw new TypeError('list argument must be an Array of Buffers.');
 
@@ -216,7 +217,7 @@ Buffer.concat = function(list, length) {
 
   if (length === undefined) {
     length = 0;
-    for (let i = 0; i < list.length; i++)
+    for (i = 0; i < list.length; i++)
       length += list[i].length;
   } else {
     length = length >>> 0;
@@ -224,7 +225,7 @@ Buffer.concat = function(list, length) {
 
   var buffer = new Buffer(length);
   var pos = 0;
-  for (let i = 0; i < list.length; i++) {
+  for (i = 0; i < list.length; i++) {
     var buf = list[i];
     buf.copy(buffer, pos);
     pos += buf.length;