Patients with unilateral right hemispheric lesions exhibited marked deficits in performance (more errors and longer response times) relative to patients either with unilateral left hemispheric lesions or with no brain damage on stereoscopically presented stimuli in a task requiring the location of a form in depth from binocular disparity cues without the aid of figure-ground contours or of monocular cues of form and depth. The stimuli were modifications of the random dot stereograms developed by B. Julesz. No deficits in the performance of the left hemisphere patients were found. The results are consistent with the hypothesis of relative dominance of the right hemisphere for stereopsis in the absence of monocular cues of form and depth. © 1969.