diff --git a/extract.js b/extract.js
index 3d682d1..6f3d3c6 100644
--- a/extract.js
+++ b/extract.js
@@ -3,7 +3,7 @@ var util = require('util');
 var bl = require('bl');
 var headers = require('./headers');
 
-var Writable = stream.Writable;
+var Writable = stream.Writable || require('readable-stream').Writable;
 var PassThrough = stream.PassThrough || require('readable-stream').PassThrough;
 
 var noop = function() {};
diff --git a/pack.js b/pack.js
index 9b94edd..d43fd9d 100644
--- a/pack.js
+++ b/pack.js
@@ -3,8 +3,8 @@ var util = require('util');
 var eos = require('end-of-stream');
 var headers = require('./headers');
 
-var Readable = stream.Readable;
-var Writable = stream.Writable;
+var Readable = stream.Readable || require('readable-stream').Readable;
+var Writable = stream.Writable || require('readable-stream').Writable;
 
 var END_OF_TAR = new Buffer(1024);
 END_OF_TAR.fill(0);