The present paper reports on 370 strabismic patients who underwent surgery after they had reached visual adulthood (ages 9-81). Surgery was performed for 183 exodeviations (50%), 139 esodeviations (37%) and 48 hypertropias. Patients desiring cosmetic improvement formed the largest group (172 cases, 46.5%). Most of these patients had been suffering from neglected concomitant heterotropias since childhood, but 17% attained subnormal binocular vision. To assess the risk of diplopia preoperatively, the deviation was fully corrected with prisms. Although intolerable persistent postoperative diplopia is a very rare event, the risk of this complication must be clearly pointed out to all visually adult patients. Apparently most adults, even those who have an anomalous retinal correspondence, respond as necessary to the new position of the eye and learn to ignore, suppress or fuse an initial postoperative diplopia. The best surgical results, in terms of restoration of binocular vision, were obtained in cases of intermittent exotropia and manifest exotropia without amblyopia.