diff --git a/aiocache/factory.py b/aiocache/factory.py
index 4037b815..81975790 100644
--- a/aiocache/factory.py
+++ b/aiocache/factory.py
@@ -137,9 +137,13 @@ def set_config(self, config):
 
         All keys in the config are optional, if they are not passed the defaults
         for the specified class will be used.
+
+        If a config key already exists, it will be updated with the new values.
         """
         if "default" not in config:
             raise ValueError("default config must be provided")
+        for config_name in config.keys():
+            self._caches.pop(config_name, None)
         self._config = config
 
 
diff --git a/tests/ut/test_factory.py b/tests/ut/test_factory.py
index b6e53f45..26f98542 100644
--- a/tests/ut/test_factory.py
+++ b/tests/ut/test_factory.py
@@ -2,7 +2,7 @@
 
 from aiocache import SimpleMemoryCache, RedisCache, caches
 from aiocache.factory import _class_from_string, _create_cache
-from aiocache.serializers import PickleSerializer
+from aiocache.serializers import JsonSerializer, PickleSerializer
 from aiocache.plugins import TimingPlugin, HitMissRatioPlugin
 
 
@@ -212,6 +212,41 @@ def test_set_empty_config(self):
         with pytest.raises(ValueError):
             caches.set_config({})
 
+    def test_set_config_updates_existing_values(self):
+        assert not isinstance(caches.get('default').serializer, JsonSerializer)
+        caches.set_config({
+            'default': {
+                'cache': "aiocache.SimpleMemoryCache",
+                'serializer': {
+                    'class': "aiocache.serializers.JsonSerializer"
+                }
+            }
+        })
+        assert isinstance(caches.get('default').serializer, JsonSerializer)
+
+    def test_set_config_removes_existing_caches(self):
+        caches.set_config({
+            'default': {
+                'cache': "aiocache.SimpleMemoryCache",
+            },
+            'alt': {
+                'cache': "aiocache.SimpleMemoryCache",
+            },
+        })
+        caches.get('default')
+        caches.get('alt')
+        assert len(caches._caches) == 2
+
+        caches.set_config({
+            'default': {
+                'cache': "aiocache.SimpleMemoryCache",
+            },
+            'alt': {
+                'cache': "aiocache.SimpleMemoryCache",
+            },
+        })
+        assert caches._caches == {}
+
     def test_set_config_no_default(self):
         with pytest.raises(ValueError):
             caches.set_config({