diff --git a/build/files.js b/build/files.js
index bc0fe5b493..c97395b2d4 100644
--- a/build/files.js
+++ b/build/files.js
@@ -72,7 +72,20 @@ const headRegexp = /(^module.exports = \w+;?)/m
 
     , isArrayDefine = [
           headRegexp
-        , '$1\n\n/*<replacement>*/\nvar isArray = require(\'isarray\');\n/*</replacement>*/\n'
+        , `$1
+
+/*<replacement>*/
+// from https://github.com/juliangruber/isarray/blob/aa39e3199004330bd72daa46207bf22f7ea5be17/index.js
+// MIT Licenced
+// Copyright (c) 2013 Julian Gruber <julian@juliangruber.com>
+
+var toString = {}.toString;
+
+var isArray = Array.isArray || function (arr) {
+  return toString.call(arr) == '[object Array]';
+};
+/*</replacement>*/
+`
       ]
 
     , isArrayReplacement = [
@@ -207,8 +220,8 @@ module.exports['_stream_readable.js'] = [
   , altIndexOfUseReplacement
   , instanceofReplacement
   , stringDecoderReplacement
-  , isArrayDefine
   , isArrayReplacement
+  , isArrayDefine
   , debugLogReplacement
   , utilReplacement
   , stringDecoderReplacement
diff --git a/lib/_stream_readable.js b/lib/_stream_readable.js
index eed7827e37..9e2c91dad0 100644
--- a/lib/_stream_readable.js
+++ b/lib/_stream_readable.js
@@ -7,7 +7,15 @@ var processNextTick = require('process-nextick-args');
 /*</replacement>*/
 
 /*<replacement>*/
-var isArray = require('isarray');
+// from https://github.com/juliangruber/isarray/blob/aa39e3199004330bd72daa46207bf22f7ea5be17/index.js
+// MIT Licenced
+// Copyright (c) 2013 Julian Gruber <julian@juliangruber.com>
+
+var toString = {}.toString;
+
+var isArray = Array.isArray || function (arr) {
+  return toString.call(arr) == '[object Array]';
+};
 /*</replacement>*/
 
 Readable.ReadableState = ReadableState;
diff --git a/package.json b/package.json
index a5d2a0bdd7..aca4d8279c 100644
--- a/package.json
+++ b/package.json
@@ -7,7 +7,6 @@
     "buffer-shims": "^1.0.0",
     "core-util-is": "~1.0.0",
     "inherits": "~2.0.1",
-    "isarray": "~1.0.0",
     "process-nextick-args": "~1.0.6",
     "string_decoder": "~0.10.x",
     "util-deprecate": "~1.0.1"