There is limited information in the literature on the outcomes of three muscle surgery. The authors aimed to evaluate the medium term motor outcomes of three horizontal muscle surgery in 18 patients with large angle infantile esotropia of at least 55PD. The median age at surgery was 22 months (10-168). Only one child had limited lateral gaze postoperatively. The mean preoperative angle was 68.8 PD ±9.54 which reduced to 1PD (esotropia 30 to exotropia 4). Medial rectus recession was 5-6.5mm and lateral rectus resection was 7-8mm. Results within ≤10PD were achieved in 78% of cases. There was a median follow-up of 32 months (5-63). One patient needed two additional surgeries for vertical deviation. Four patients needed second surgery for residual esotropia. The mean dose / response ratio was 3.32±0.62PD/mm. The authors conclude there is a good rate of success in short and medium term. Overcorrection was not a serious problem but under correction can still occur.