http://php.he.net/manual/en/mssql.installation.php Installation The MSSQL extension is enabled by adding extension=php_mssql.dll to php.ini. To get these functions to work, you have to compile PHP with --with-mssql[=DIR], where DIR is the FreeTDS install prefix. And FreeTDS should be compiled using --enable-msdblib. Did you actually do a compile ... --with-mssql=/usr/local/freetds ... I saw you asked " ./configure [--with-apxs --with-mysql...] You actually meant mssql, right?" But I didn't see a reply about that. I searched for "--with-mssql" in my emails and did not see that in your thread, but saw Claudio Saavedra's thread from Jan 12, 2007 'Problem with PHP 4.4.4 and MSSQL in Centos' also mentioning "--with-sybase", but his solution was "I fixed it by compiling again php with --with-mssql instead of --with-sybase. Now it works perfectly". So again, I'd recommend compiling "--with-mssql". By the way anybody, why would I compile "--with-sybase" if I want to use MSSQL commands? I just checked my phpinfo on an install that has mysql and mssql. I don't even see a --with-mysql or --with-mssql like on previous servers, but I see "additional .ini files parsed" which mentions /etc/php.d/mssql.ini and /etc/php.d/mysqli.ini. Enjoy!