Purpose To determine the influence of general anesthesia and strabismus surgery on children's intellectual abilities. Design Prospective, observational study. Methods settings: Institutional. patients: Children 5 to 10 years of age receiving general anesthesia with sevoflurane and undergoing strabismus surgery were included. Intellectual abilities were examined before and 4 weeks after surgery using the Kaufman Assessment Battery for Children. Four subtests representing intellectual abilities related to complex cortical function were examined: identification of objects in a partially completed picture, reproduction of a presented design by using rubber triangles, selecting a picture that completes or is similar to another picture, and memory for location of pictures presented on a page. main outcome measures: Preoperative and postoperative age-adjusted scores of the 4 subtests of the Kaufman Assessment Battery for Children. Results The study group consisted of 21 children who underwent strabismus surgery under general anesthesia (mean duration, 51.3 minutes). The mean preoperative total score of the 4 subtests was 49.4 ± 6.2. The mean postoperative total score adjusted for potential learning effects and test–retest reliability was 48.1 ± 7.7. There was no significant postoperative change in the total score (P = .108). However, the triangle test score decreased significantly after operation (P = .019), particularly in patients with decreased stereoacuity after surgery. Conclusions General anesthesia with sevoflurane and strabismus surgery generally do not affect the intellectual abilities of complex cortical function in children 5 to 10 years of age at 4 weeks after surgery. Cortical functions related to hand–eye coordination may be affected by transient changes in postoperative stereoacuity.