Parents of children with congenital esotropia have reported improvements in their child's fine motor development and visual functions after surgery. Eighteen patients with congenital esotropia were tested pre- and post-operatively with The Bayley Scales of Infant Development to determine if these observations were valid. A three-point increase in the Bayley raw score of strabismus patients was noted after operation that is significant at the 0.01 level, as compared to the performance of age-matched controls. An improvement in fine motor skills was observed in 35% of the children, and visually directed reaching and grasping increased in 41%. Item #87 on the Bayley, which requires the child to recognize depressions without monocular clues, appears to be related specifically to depth perception. On this item, the study population showed the greatest improvement.