diff --git a/lib/document.coffee b/lib/document.coffee
index e6ed21e..53bb38e 100644
--- a/lib/document.coffee
+++ b/lib/document.coffee
@@ -80,8 +80,8 @@ class PDFDocument
         @page.content.add str
         return this # make chaining possible
         
-    write: (filename) ->
-         fs.writeFile filename, @output(), 'binary'
+    write: (filename, callback) ->
+         fs.writeFile filename, @output(), 'binary', callback
         
     output: ->
        out = []