The Callable Library can be interfaced with FORTRAN applications. You can download examples of a FORTRAN application from the ILOG web site at http://www.ilog.com/products/cplex
. Choose Tech Support; then choose Callable Library Examples. The examples were compiled on a particular platform. Since C-to-FORTRAN interfaces vary across platforms (operating system, hardware, compilers, etc.), you may need to modify the examples for your particular system.