Parameter variation in the load of a servoposition control drive requires a robust controller. The sliding mode control, which constrains the system motion to a state trajectory, provides for greater robustness than classical control schemes. The design and implementation of a brushless DC servomotor drive using sliding mode position control is described. The design procedure is outlined, and the features of practical sampling rate and supply source limitation are incorporated. The implementation of the system, based on a Motorola 68000 processor, is described, and both simulated and practical responses are presented and evaluated.