In NHibernate you can map generics like this <class name="Units.Parameter`1[System.Int32], Units" table="parameter_int" > </class> But how can I map a class like this? Set<T> where T is a Parameter<int> like this Set<Parameter<int>> My mapping hbm.xml looking like this fails <class name="Set`1[[Units.Parameter`1[System.Int32], Units]],Units" table="settable"/> I simplified my mappings a little to get my point accross very clearly. Basically I want NHibernate to map generic class which has has generic type parameter. Want I understand from googling around is that NHibernate is not able to parse the name to the correct type in TypeNameParser.Parse() which result in the following error when adding the mapping to the configuration System.ArgumentException: Exception of type 'System.ArgumentException' was thrown. Parameter name: typeName@31 Anybody found a way around this limitation?