I haven't used MATLAB (change in job) these last 5 years, so much has changed. The MATLAB documentation addresses this subject. The tricky part is understanding the argument passing -- understanding the MATLAB variable structures. They seem very simple in MATLAB because most of the complexity is hidden. The MATLAB package includes subroutines for copying data between MATLAB variables and more common FORTRAN data structures for some set of FORTRAN compilers. Those compilers are listed on the MATLAB web site. Be sure your compiler is on that list, or get one that is. Basically, read your MATLAB documentation.