We classified 103 patients (206 eyes) with infantile esotropia and an average of 8.7 years of postoperative follow-up into four outcome groups. Of 103 patients, 28 (27%) had subnormal binocular vision; 24 (23%) had microtropia; 43 (42%) had small-angle deviation (< 20 prism diopters); and eight (8%) had large-angle deviation. A chi 2 analysis showed a significant difference (chi 2 = 16.22, P = .005) in the distribution of amblyopia among these four outcome groups. Visual acuity of 20/30 or better was attained in 174 of the 206 eyes (84%). The eyes of all 28 patients in the subnormal binocular vision group remained aligned after an average of eight years. In contrast, the eyes of six of 30 patients (20%) in the microtropia group and 11 of 43 (26%) in the small-angle deviation group lost the stability of horizontal alignment. We found that the two variables of latent-manifest nystagmus and persistent amblyopia at the time of surgery lead to less satisfactory outcomes. In contrast, patients with smaller preoperative angle of deviation or surgery completed before 1 year of age demonstrated an increased incidence of optimal (subnormal binocular vision) or desirable (microtropia) results. We recommend performing surgery after amblyopia has been thoroughly treated, and, whenever possible, completing the surgical treatment by 1 year of age.