diff --git a/riak/riak_object.py b/riak/riak_object.py
index b4ddabad..2cd9af55 100644
--- a/riak/riak_object.py
+++ b/riak/riak_object.py
@@ -91,6 +91,11 @@ def set_data(self, data):
         :rtype: data
         """
         self._data = data
+        if MD_CTYPE not in self._metadata:
+            if self._encode_data:
+                self.set_content_type("application/json")
+            else:
+                self.set_content_type("application/octet-stream")
         return self
 
     def get_encoded_data(self):
diff --git a/riak/tests/test_all.py b/riak/tests/test_all.py
index 6986f54a..0d769554 100644
--- a/riak/tests/test_all.py
+++ b/riak/tests/test_all.py
@@ -348,6 +348,26 @@ def test_link_walking(self):
         results = obj.link("bucket", "tag").run()
         self.assertEqual(len(results), 1)
 
+    def test_store_of_missing_object(self):
+        bucket = self.client.bucket("bucket")
+        # for json objects 
+        o = bucket.get("nonexistent_key_json")
+        self.assertEqual(o.exists(), False)
+        o.set_data({"foo" : "bar"})
+        o = o.store()
+        self.assertEqual(o.get_data(), {"foo" : "bar"})
+        self.assertEqual(o.get_content_type(), "application/json")
+        o.delete()
+        # for binary objects
+        o = bucket.get_binary("nonexistent_key_binary")
+        self.assertEqual(o.exists(), False)
+        o.set_data("1234567890")
+        o = o.store()
+        self.assertEqual(o.get_data(), "1234567890")
+        self.assertEqual(o.get_content_type(), "application/octet-stream")
+        o.delete()
+
+
     def test_search_integration(self):
         if SKIP_SEARCH:
             return True