diff --git a/modules/mol/base/pymod/export_residue.cc b/modules/mol/base/pymod/export_residue.cc
index 905c6b5155cf42c0bd1fb187296e9e0f799351e5..27575f800ff1b37971cde43d484557ebe3ed855d 100644
--- a/modules/mol/base/pymod/export_residue.cc
+++ b/modules/mol/base/pymod/export_residue.cc
@@ -71,6 +71,7 @@ void export_Residue()
     .def(self+int())
     .def(self-int())    
   ;
+  implicitly_convertible<int, ResNum>();
   {
     scope sec_struct_scope=class_<SecStructure>("SecStructure", init<>())
       .def(init<char>())