Hi, This branch improves numpy import times quite significantly on slow machines: http://github.com/cournape/numpy/tree/noinspect One of the main culprit is ma, because of inspect (inspect is extremely slow to import; as a data point, python -c "import inspect" takes 67 ms vs python -c "" taking 22 ms, and python -c "import numpy" taking 158 ms on my machine). Since inspect is used in quite a few places, and that we only use it to extract arguments from a function, I added a small numpy.lib.inspect module, and change the import in numpy.ma. I copied the inspect module of python 2.4.4 to ensure maximum compatibility. This speed up the import times from 158 ms to 108 ms ~ 30 % speed improvement. On recent machines, the speedup is less impressive, but still in the 20 % range. I think it largely worths it, and will integrate this unless someone is strongly against it or see a problem with the approach, cheers, David