I am trying to expose a class with a boost::uuids::uuid member to Python. The class is pretty simple: class Article { public: boost::uuids::uuid uuid; }; which is exposed like this: article .def(init<boost::uuids::uuid, Article::Type>((arg("uuid"))) .def_readwrite("uuid", &Article::uuid); and I have basic converter registered (see https://gist.github.com/wichert/5543390 , it is a bit large to include in this email). This compiles fine and the uuid convertor works correctly when trying converting from python to C++, but trying to access the uuid property results in "TypeError: No Python class registered for C++ class boost::uuids::uuid". I don't understand why that doesn't work; does anyone see what I missed? Wichert.