Platform: Windows 7, 64 bit (x64), Visual Studio 2008 I chose Python & Swig binding as the scripting environment of the application. As a prototype, created a simple VS solution with main() which initializes Python (Py_Initalize, Py_setPyHome, etc) & executes test.py. In the same solution created another project which is a DLL of a simple class. Used SWIG to wrap this class. This DLL is the _MyClasses.pyd. test.py creates the objects of my class & calls its member functions. All this works like a charm in the Release mode. But does not work in Debug mode (even tried banging my head on the laptop ;-) ). Output of my work looks like this (in both release & debug): x64 -debug - _MyClasses.pyd - MyClasses.py - test.exe - test.py - python26.dll - python26_d.dll Note that the debug version is linked against python26_d.lib. Had to build python myself for this! test.py import MyClasses print "ello" m = MyClasses.Male("John Doe", 25) print m.getType() Male is the C++ class. The problem: Traceback (most recent call last): File "test.py", line 6, in <module> import MyClasses File "...\x64\Debug\MyClasses.py", line 25, in <module> _MyClasses = swig_import_helper() File "...\x64\Debug\MyClasses.py", line 17, in swig_imp ort_helper import _MyClasses ImportError: No module named _MyClasses [15454 refs] I am used to Makefiles & am new to Visual Studio. I dont know who the culprit is here: Swig, The debug build of Python, Visual Studio, my stupidity. Thank you in advance. It will be a great help.