I installed Boost 1.32 to VS 2003 and MINGW 3.4.2 (got 80 failures for the second), and now I am trying to use it with both but the compiler's can't find the boost header files by their own. For example the source code: #include <boost/static_assert.hpp> int main() { int i=1; BOOST_STATIC_ASSERT(i==1); } produces: C:\c>g++ temp.cpp -o temp.exe temp.cpp:1:35: boost/static_assert.hpp: No such file or directory temp.cpp: In function `int main()': temp.cpp:7: error: `BOOST_STATIC_ASSERT' undeclared (first use this function) temp.cpp:7: error: (Each undeclared identifier is reported only once for each fu nction it appears in.) C:\c>cl /EHsc temp.cpp Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 13.10.3077 for 80x86 Copyright (C) Microsoft Corporation 1984-2002. All rights reserved. temp.cpp temp.cpp(1) : fatal error C1083: Cannot open include file: 'boost/static_assert. hpp': No such file or directory C:\c> I tried everything I could think like adding the c:\Boost folder and subfolders in PATH environment variable, or explicitly #include the file with its entire path, with no result. What am I missing here? Thanks in advance.