diff --git a/zarr/storage.py b/zarr/storage.py
index 17c6a88b46..12154c29e4 100644
--- a/zarr/storage.py
+++ b/zarr/storage.py
@@ -1267,9 +1267,6 @@ def __setitem__(self, key, value):
             else:
                 keyinfo.external_attr = 0o644 << 16     # ?rw-r--r--
 
-            if isinstance(value, str):
-                value = value.encode("utf-8")
-
             self.zf.writestr(keyinfo, value)
 
     def __delitem__(self, key):
diff --git a/zarr/tests/test_storage.py b/zarr/tests/test_storage.py
index 5488eeab52..31433c8eff 100644
--- a/zarr/tests/test_storage.py
+++ b/zarr/tests/test_storage.py
@@ -9,6 +9,7 @@
 import unittest
 from contextlib import contextmanager
 from pickle import PicklingError
+from zipfile import ZipFile
 
 import numpy as np
 import pytest
@@ -947,6 +948,21 @@ def test_popitem(self):
         with pytest.raises(NotImplementedError):
             store.popitem()
 
+    def test_permissions(self):
+        store = ZipStore('data/store.zip', mode='w')
+        store['foo'] = b'bar'
+        store['baz/'] = b''
+        store.flush()
+        store.close()
+        z = ZipFile('data/store.zip', 'r')
+        info = z.getinfo('foo')
+        perm = oct( info.external_attr >> 16 )
+        assert perm == '0o644'
+        info = z.getinfo('baz/')
+        perm = oct( info.external_attr >> 16 )
+        assert perm == '0o40775'
+        z.close()
+
 
 class TestDBMStore(StoreTests, unittest.TestCase):