diff --git a/code/nel/include/nel/misc/class_id.h b/code/nel/include/nel/misc/class_id.h
index 5556fcd08..5d05465ef 100644
--- a/code/nel/include/nel/misc/class_id.h
+++ b/code/nel/include/nel/misc/class_id.h
@@ -23,6 +23,7 @@
 
 namespace	NLMISC
 {
+	class IStream;
 
 // ***************************************************************************
 /**
@@ -56,6 +57,8 @@ public:
 	inline uint32 b() const { return (uint32)(Uid & 0xFFFFFFFFL); }
 	inline void setA(uint32 a) { Uid = ((uint64)a<<32) | (Uid & 0xFFFFFFFFL); }
 	inline void setB(uint32 b) { Uid = (Uid & 0xFFFFFFFF00000000L) | b; }
+
+	void serial(NLMISC::IStream &s);
 };
 
 /**
diff --git a/code/nel/src/misc/class_id.cpp b/code/nel/src/misc/class_id.cpp
index e705c26a8..b13bbc8d4 100644
--- a/code/nel/src/misc/class_id.cpp
+++ b/code/nel/src/misc/class_id.cpp
@@ -18,7 +18,7 @@
 
 #include "nel/misc/class_id.h"
 
-
+#include "nel/misc/stream.h"
 
 
 namespace	NLMISC
@@ -27,6 +27,11 @@ namespace	NLMISC
 
 const	CClassId	CClassId::Null(0);
 
+void CClassId::serial(NLMISC::IStream &s)
+{
+	s.serial(Uid);
+}
+
 
 }