diff --git a/rtv/objects.py b/rtv/objects.py
index b6a42a1..48f0074 100644
--- a/rtv/objects.py
+++ b/rtv/objects.py
@@ -643,14 +643,16 @@ class KeyMap(object):
         self.set_bindings(bindings)
 
     def set_bindings(self, bindings):
-        # Clear the keymap before applying the bindings to avoid confusion.
-        # If a user defines custom bindings in their config file, they must
-        # explicitly define ALL of the bindings.
-        self._keymap = {}
+        new_keymap = {}
         for command, keys in bindings.items():
             if not isinstance(command, Command):
                 command = Command(command)
-            self._keymap[command] = keys
+            new_keymap[command] = keys
+
+        if not self._keymap:
+            self._keymap = new_keymap
+        else:
+            self._keymap.update(new_keymap)
 
     def get(self, command):
         if not isinstance(command, Command):
@@ -694,4 +696,4 @@ class KeyMap(object):
 
         except (AttributeError, ValueError, TypeError):
             raise exceptions.ConfigError('Invalid configuration! "%s" is not a '
-                                         'valid key' % key)
\ No newline at end of file
+                                         'valid key' % key)
diff --git a/tests/test_config.py b/tests/test_config.py
index 51c40b6..060a6e4 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -136,9 +136,10 @@ def test_config_from_file():
 
         fargs, fbindings = Config.get_file(filename=fp.name)
         config = Config(**fargs)
+        default_keymap = config.keymap._keymap.copy()
         config.keymap.set_bindings(fbindings)
         assert config.config == {}
-        assert config.keymap._keymap == {}
+        assert config.keymap._keymap == default_keymap
 
         # [rtv]
         rows = ['{0}={1}'.format(key, val) for key, val in args.items()]
@@ -224,4 +225,4 @@ def test_config_history():
 
         config.delete_history()
         assert len(config.history) == 0
-        assert not os.path.exists(fp.name)
\ No newline at end of file
+        assert not os.path.exists(fp.name)
diff --git a/tests/test_objects.py b/tests/test_objects.py
index 1ac11ca..e3d8213 100644
--- a/tests/test_objects.py
+++ b/tests/test_objects.py
@@ -370,13 +370,17 @@ def test_objects_keymap():
         keymap.get('downvote')
     assert 'DOWNVOTE' in six.text_type(e)
 
-    # Updating the bindings wipes out the old ones
     bindings = {'refresh': ['a', 0x12, '<LF>', '<KEY_UP>']}
+    bindings2 = {'upvote': ['b', 0x13, '<KEY_DOWN>']}
+    keymap._keymap = {}
     keymap.set_bindings(bindings)
     assert keymap.get('refresh')
     with pytest.raises(exceptions.ConfigError) as e:
         keymap.get('upvote')
     assert 'UPVOTE' in six.text_type(e)
+    keymap.set_bindings(bindings2)
+    assert keymap.get('refresh')
+    assert keymap.get('upvote')
 
     # Strings should be parsed correctly into keys
     assert KeyMap.parse('a') == 97
@@ -589,4 +593,4 @@ def test_objects_navigator_flip():
     nav.flip(3)
     assert nav.page_index == 2
     assert nav.cursor_index == 3
-    assert not nav.inverted
\ No newline at end of file
+    assert not nav.inverted