diff --git a/compose/config.py b/compose/config.py
index 668d2b726..0cd7c1ae6 100644
--- a/compose/config.py
+++ b/compose/config.py
@@ -318,18 +318,30 @@ def merge_volumes(base, override):
 
 
 def dict_from_volumes(volumes):
-    return dict(split_volume(v) for v in volumes)
-
-
-def split_volume(volume):
-    if ':' in volume:
-        return reversed(volume.split(':', 1))
+    if volumes:
+        return dict(split_volume(v) for v in volumes)
     else:
-        return (volume, None)
+        return {}
 
 
 def volumes_from_dict(d):
-    return ["%s:%s" % (host_path, container_path) for (container_path, host_path) in d.items()]
+    return [join_volume(v) for v in d.items()]
+
+
+def split_volume(string):
+    if ':' in string:
+        (host, container) = string.split(':', 1)
+        return (container, host)
+    else:
+        return (string, None)
+
+
+def join_volume(pair):
+    (container, host) = pair
+    if host is None:
+        return container
+    else:
+        return ":".join((host, container))
 
 
 def expand_path(working_dir, path):
diff --git a/tests/unit/config_test.py b/tests/unit/config_test.py
index 013ad5031..8deb457af 100644
--- a/tests/unit/config_test.py
+++ b/tests/unit/config_test.py
@@ -39,6 +39,47 @@ class ConfigTest(unittest.TestCase):
         config.make_service_dict('foo', {'ports': ['8000']})
 
 
+class MergeTest(unittest.TestCase):
+    def test_merge_volumes_empty(self):
+        service_dict = config.merge_service_dicts({}, {})
+        self.assertNotIn('volumes', service_dict)
+
+    def test_merge_volumes_no_override(self):
+        service_dict = config.merge_service_dicts(
+            {'volumes': ['/foo:/code', '/data']},
+            {},
+        )
+        self.assertEqual(set(service_dict['volumes']), set(['/foo:/code', '/data']))
+
+    def test_merge_volumes_no_base(self):
+        service_dict = config.merge_service_dicts(
+            {},
+            {'volumes': ['/bar:/code']},
+        )
+        self.assertEqual(set(service_dict['volumes']), set(['/bar:/code']))
+
+    def test_merge_volumes_override_explicit_path(self):
+        service_dict = config.merge_service_dicts(
+            {'volumes': ['/foo:/code', '/data']},
+            {'volumes': ['/bar:/code']},
+        )
+        self.assertEqual(set(service_dict['volumes']), set(['/bar:/code', '/data']))
+
+    def test_merge_volumes_add_explicit_path(self):
+        service_dict = config.merge_service_dicts(
+            {'volumes': ['/foo:/code', '/data']},
+            {'volumes': ['/bar:/code', '/quux:/data']},
+        )
+        self.assertEqual(set(service_dict['volumes']), set(['/bar:/code', '/quux:/data']))
+
+    def test_merge_volumes_remove_explicit_path(self):
+        service_dict = config.merge_service_dicts(
+            {'volumes': ['/foo:/code', '/quux:/data']},
+            {'volumes': ['/bar:/code', '/data']},
+        )
+        self.assertEqual(set(service_dict['volumes']), set(['/bar:/code', '/data']))
+
+
 class EnvTest(unittest.TestCase):
     def test_parse_environment_as_list(self):
         environment =[