I get the same behaviour as Robert (the correct one). In [13]: sys.version Out[13]: '2.4.2 (#2, Sep 30 2005, 21:19:01) \n[GCC 4.0.2 20050808 (prerelease) (Ubuntu 4.0.1-4ubuntu8)]' In [14]: numpy.__version__ Out[14]: '0.9.5.2044' Johannes