diff --git a/include/boost/python/converter/registry.hpp b/include/boost/python/converter/registry.hpp
index e037bbcc..368adcc6 100644
--- a/include/boost/python/converter/registry.hpp
+++ b/include/boost/python/converter/registry.hpp
@@ -30,7 +30,7 @@ namespace registry
   BOOST_PYTHON_DECL void insert(to_python_function_t, type_info, PyTypeObject const* (*to_python_target_type)() = 0);
 
   // Insert an lvalue from_python converter
-  BOOST_PYTHON_DECL void insert(void* (*convert)(PyObject*), type_info, PyTypeObject const* (*expected_pytype)() = 0);
+  BOOST_PYTHON_DECL void insert(convertible_function, type_info, PyTypeObject const* (*expected_pytype)() = 0);
 
   // Insert an rvalue from_python converter
   BOOST_PYTHON_DECL void insert(
diff --git a/src/converter/registry.cpp b/src/converter/registry.cpp
index d203ea8c..aa20c3f6 100644
--- a/src/converter/registry.cpp
+++ b/src/converter/registry.cpp
@@ -243,7 +243,7 @@ namespace registry
   }
 
   // Insert an rvalue from_python converter
-  void insert(void* (*convertible)(PyObject*)
+  void insert(convertible_function convertible
               , constructor_function construct
               , type_info key
               , PyTypeObject const* (*exp_pytype)())
@@ -261,7 +261,7 @@ namespace registry
   }
 
   // Insert an rvalue from_python converter
-  void push_back(void* (*convertible)(PyObject*)
+  void push_back(convertible_function convertible
               , constructor_function construct
               , type_info key
               , PyTypeObject const* (*exp_pytype)())