diff --git a/Code/CompleteJamroot.py b/Code/CompleteJamroot.py
index 3def3da8e..c534e3c65 100644
--- a/Code/CompleteJamroot.py
+++ b/Code/CompleteJamroot.py
@@ -5,7 +5,8 @@ except ImportError:
     print >>sys.stderr,"ERROR: numpy module not found.\nThe RDKit python wrappers will not build correctly, but the rest of the code should be fine."
     sys.exit(0)
 
-incDir = os.path.join(os.path.split(numpy.__file__)[0],'core','include')
+numpyDir=os.path.split(numpy.__file__)[0].replace('\\','/')
+incDir = '/'.join((numpyDir,'core','include'))
 inD = file('Jamroot.in','r').read()
 print >>file('Jamroot','w+'),inD.replace('NUMPY_INCLUDE_DIR',incDir)