This study describes a large cohort of 248 patients with adult onset esotropia (ET) due to a range of causes and details preoperative characteristics, operative procedures and surgical outcomes. Mean age at diagnosis was 52 years. Diagnoses included cranial nerve palsy, thyroid eye disease, age-related distance ET and decompensated ET. Preoperative stereopsis was present in 17%. Surgery was performed elsewhere for 13%, 3% had preoperative BT and half had prism correction. Surgery was tailored to the individual cause. Surgical options included recession / resection, unilateral medial rectus recession, bilateral medial rectus recession, lateral rectus resection, plus / minus adjustable sutures. At two months follow-up, 80% were within 10PD of ortho and diplopia in primary gaze had resolved in 22%. Reoperation rate was low at 15%. Stereopsis was regained by 75%. Long-term prisms were needed by 6%. The authors conclude surgery is a successful, low risk option for treatment of diplopia due to esotropia in adults.