There has been a tremendous growth in the use of evoked potential techniques in the orthopedic and neurosurgical operating rooms. The popularity of evoked potential monitoring has evolved from the surgeon's need to know the impact of surgical manipulations on the central nervous system. It is safe and practical to monitor the electrophysiological function of the cortex, brainstem, cranial nerves, and motor and sensory pathways in the spinal cord utilizing evoked potential techniques. This paper presents a review of these techniques.