diff --git a/lib/buffer.js b/lib/buffer.js
index 797d4d67e6b9..e1fcdb4044bb 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -7,6 +7,10 @@ function toHex (n) {
   return n.toString(16);
 }
 
+Buffer.isBuffer = function (b) {
+  return b instanceof Buffer;
+};
+
 Buffer.prototype.inspect = function () {
   var s = "<Buffer ";
   for (var i = 0; i < this.length; i++) {
diff --git a/lib/fs.js b/lib/fs.js
index efc7ab11ef56..91eb74094ca4 100644
--- a/lib/fs.js
+++ b/lib/fs.js
@@ -150,7 +150,7 @@ fs.openSync = function (path, flags, mode) {
 };
 
 fs.read = function (fd, buffer, offset, length, position, callback) {
-  if (!(buffer instanceof Buffer)) {
+  if (!Buffer.isBuffer(buffer)) {
     // legacy string interface (fd, length, position, encoding, callback)
     var cb = arguments[4],
         encoding = arguments[3];
@@ -175,7 +175,7 @@ fs.read = function (fd, buffer, offset, length, position, callback) {
 
 fs.readSync = function (fd, buffer, offset, length, position) {
   var legacy = false;
-  if (!(buffer instanceof Buffer)) {
+  if (!Buffer.isBuffer(buffer)) {
     // legacy string interface (fd, length, position, encoding, callback)
     legacy = true;
     encoding = arguments[3];
@@ -198,7 +198,7 @@ fs.readSync = function (fd, buffer, offset, length, position) {
 };
 
 fs.write = function (fd, buffer, offset, length, position, callback) {
-  if (!(buffer instanceof Buffer)) {
+  if (!Buffer.isBuffer(buffer)) {
     // legacy string interface (fd, data, position, encoding, callback)
     callback = arguments[4];
     position = arguments[2];
@@ -212,7 +212,7 @@ fs.write = function (fd, buffer, offset, length, position, callback) {
 };
 
 fs.writeSync = function (fd, buffer, offset, length, position) {
-  if (!(buffer instanceof Buffer)) {
+  if (!Buffer.isBuffer(buffer)) {
     // legacy string interface (fd, data, position, encoding)
     position = arguments[2];
 
@@ -384,7 +384,7 @@ fs.writeFile = function (path, data, encoding_, callback) {
     if (openErr) {
       if (callback) callback(openErr);
     } else {
-      var buffer = data instanceof Buffer ? data : new Buffer(data, encoding);
+      var buffer = Buffer.isBuffer(data) ? data : new Buffer(data, encoding);
       writeAll(fd, buffer, callback);
     }
   });
@@ -864,7 +864,7 @@ WriteStream.prototype.write = function (data) {
     cb = arguments[arguments.length-1];
   }
 
-  if (data instanceof Buffer) {
+  if (Buffer.isBuffer(data)) {
     this._queue.push([fs.write, data, 0, data.length, null, cb]);
   } else {
     var encoding = 'utf8';
diff --git a/lib/http.js b/lib/http.js
index 66869740ec35..94c390f78fdb 100644
--- a/lib/http.js
+++ b/lib/http.js
@@ -433,7 +433,7 @@ OutgoingMessage.prototype.write = function (chunk, encoding) {
   }
 
   if (typeof chunk !== "string"
-      && !(chunk instanceof Buffer)
+      && !Buffer.isBuffer(chunk)
       && !Array.isArray(chunk)) {
     throw new TypeError("first argument must be a string, Array, or Buffer");
   }