diff --git a/mergers/dict/update.py b/mergers/dict/update.py
index dd834f0..69e849d 100644
--- a/mergers/dict/update.py
+++ b/mergers/dict/update.py
@@ -11,6 +11,9 @@
 class DictUpdate(BaseDictMerger):
 
     def merge(self, first, second):
+        if second is None:
+            return first
+
         ret = first.copy()
         ret.update(second)
         return ret