Fifty-five patients with moderate angle exotropia of 15 to 20 prism diopters were surgically treated with a unilateral lateral rectus recession of 7.0, 7.5, or 8.0 mm. The mean age at surgery was 14.5 years. The mean preoperative deviation was 18.0 delta. The mean lateral rectus recession was 7.6 mm. At the initial postoperative follow up, all patients were either a small-angle exotropia or esotropia, or orthophoric. Twenty-eight of the 55 patients (51%) were orthophoric at their most recent follow up. Twenty-four patients (44%) were undercorrected, with 22 of these having residual exodeviations less than 8 delta. Three patients (5%) were overcorrected.