diff --git a/csla_binary/binary_writer.py b/csla_binary/binary_writer.py
index 3eaf400..b836342 100644
--- a/csla_binary/binary_writer.py
+++ b/csla_binary/binary_writer.py
@@ -94,6 +94,9 @@ class CslaBinaryWriter:
 	
 	def write_object(self, value):
 		# CslaBinaryWriter.Write(...)
+		if value is None:
+			return self.write_object_null()
+		
 		if isinstance(value, bool):
 			return self.write_object_bool(value)
 		
@@ -131,6 +134,9 @@ class CslaBinaryWriter:
 		self.stream.write(bytes([CslaKnownTypes.Int32.value]))
 		self.write_int32(value)
 	
+	def write_object_null(self):
+		self.stream.write(bytes([CslaKnownTypes.Null.value]))
+	
 	def write_object_string(self, value):
 		# CslaBinaryWriter.Write(string)
 		self.stream.write(bytes([CslaKnownTypes.String.value]))