Cortical potentials evoked by dynamic random dot stereograms were recorded in 15 normal subjects and 19 patients with impaired stereoscopic vision. The potentials obtained were compaired with those evoked by similarly arranged checkerboard contrast stimuli, binocularly presented. The two modes of stimulation yielded potentials of similar component latencies but the stereoscopically evoked component amplitudes were significantly lower. In nine-channel recordings the stereoscopically evoked potentials were found to be located farther anterior topographically, suggesting a different neural generating mechanism. Patients with impaired stereoscopic vision had lower amplitudes and longer peak latencies than normal subjects. In addition, larger disparities had to be used to elicit a response in these patients. There was a high degree of correlation between the disparity thresholds determined by evoked cortical potentials and those obtained by sensory measurements.