Abstract: A voice command system for a robot arm is designed as a part of a research project. The methodology adopted is based on a spotted words recognition system based on a robust HMM (Hidden Markove Model) technique with cepstral coefficients as parameters used in automatic speech recognition system. To implement the approach on a real-time application, a Personal Computer parallel port interface was designed to control the movement of a set of stepper motors. The designed system user can control the movements of 5 Degree of Freedom (DOF) for a robot arm using a vocal phrase containing spotted words. Other applications are proposed.