As all of you know, MATLAB is a powerful engineering language. Because of some limitation, some tasks take very long time to proceed. Also MATLAB is an interpreter not a compiler. For this reason, executing a MATLAB program (m file) is time consuming. For solving this problem, Mathworks provides us C Math Library or in common language, MATLAB API. A developer can employ these APIs to solve engineering problems very fast and easy. This article is about how can use these APIs.