diff --git a/src/swsssdk/configdb.py b/src/swsssdk/configdb.py
index 0df1359fc..34d292649 100644
--- a/src/swsssdk/configdb.py
+++ b/src/swsssdk/configdb.py
@@ -134,10 +134,11 @@ def __typed_to_raw(self, typed_data):
         raw_data = {}
         for key in typed_data:
             value = typed_data[key]
-            if type(value) is list:
-                raw_data[key+'@'] = ','.join(value)
-            else:
-                raw_data[key] = value
+            if value is not None:
+                if type(value) is list:
+                    raw_data[key+'@'] = ','.join(value)
+                else:
+                    raw_data[key] = value
         return raw_data
 
     @staticmethod