Hello, I jsut built numpy 1.4.1 on my mac (64bit only no universal) Now f2py fails building any fortran code... my python: 2.6.5 meryem /svn/cdat/trunk >gcc --version i686-apple-darwin10-gcc-4.2.1 (GCC) 4.2.1 (Apple Inc. build 5646) (dot 1) Copyright (C) 2007 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. meryem /svn/cdat/trunk >gfortran --version GNU Fortran (GCC) 4.5.0 20100107 (experimental) Copyright (C) 2009 Free Software Foundation, Inc. GNU Fortran comes with NO WARRANTY, to the extent permitted by law. You may redistribute copies of GNU Fortran under the terms of the GNU General Public License. For more information about these matters, see the file named COPYING I'm also attaching bzipped logs of my numpy and scipy (as an example that would be familiar to you guys) installs. scipy obviously fails because the f2py doesn't work. Thx, C.