diff --git a/fake_filesystem.py b/fake_filesystem.py
index 2eac281..7a35b48 100644
--- a/fake_filesystem.py
+++ b/fake_filesystem.py
@@ -89,6 +89,8 @@
 import sys
 import time
 import warnings
+import binascii
+
 try:
   import cStringIO as io  # pylint: disable-msg=C6204
 except ImportError:
@@ -224,7 +226,7 @@ def SetContents(self, contents):
     """
     # convert a byte array to a string
     if sys.version_info >= (3, 0) and isinstance(contents, bytes):
-      contents = ''.join(chr(i) for i in contents)
+      contents = binascii.hexlify(contents).decode('ascii')
     self.contents = contents
     self.st_size = len(contents)
     self.epoch += 1
@@ -1968,7 +1970,7 @@ def __init__(self, file_object, update=False, read=False, append=False,
         if sys.version_info >= (3, 0) and binary:
           io_class = io.BytesIO
           if contents and isinstance(contents, str):
-            contents = bytes(contents, 'ascii')
+            contents = binascii.unhexlify(contents)
         if contents:
           if update:
             self._io = io_class(**newline_arg)
diff --git a/fake_filesystem_test.py b/fake_filesystem_test.py
old mode 100644
new mode 100755
index 0e32d81..eb9a702
--- a/fake_filesystem_test.py
+++ b/fake_filesystem_test.py
@@ -23,6 +23,7 @@
 import sys
 import time
 import unittest
+import binascii
 
 import fake_filesystem
 
@@ -2492,7 +2493,7 @@ def setUp(self):
     self.file = fake_filesystem.FakeFileOpen(self.filesystem)
     self.os = fake_filesystem.FakeOsModule(self.filesystem)
     self.file_path = 'some_file'
-    self.file_contents = b'binary contents'
+    self.file_contents = b'real binary contents: \x1f\x8b'
     self.filesystem.CreateFile(self.file_path, contents=self.file_contents)
 
   def OpenFakeFile(self, mode):
@@ -2520,7 +2521,10 @@ def testWriteBinary(self):
     # reopen the file in text mode
     fake_file = self.OpenFakeFile('wb')
     fake_file = self.WriteAndReopenFile(fake_file, mode='r')
-    self.assertEqual(self.file_contents.decode('ascii'), fake_file.read())
+    if sys.version_info >= (3, 0):
+      self.assertEqual(binascii.hexlify(self.file_contents).decode('ascii'), fake_file.read())
+    else:
+      self.assertEqual(self.file_contents, fake_file.read())
 
   def testWriteAndReadBinary(self):
     fake_file = self.OpenFileAndSeek('w+b')