Objective: To evaluate the effect of the posterior fixation of the mass of the inferior oblique muscle  in treating inferior oblique overaction (IOOA) with small-angle hypertropia and V pattern strabismus.  Methods: A retrospective study of 16 cases of patients who had undergone inferior oblique mass posterior  fixation was performed. Among the 16 patients (22 eyes), 10 patients had small-angle hypertropia in  their primary gaze (≤5 prism diopters), 8 patients had unilateral superior oblique palsies, 2 patients had  horizontal strabismus with a mild monocular IOOA; and the other 6 patients had V pattern strabismus.  Patients were followed from 3 to 6 months. The vertical deviation in the primary position, degree of the V  pattern and objective cyclodeviations were compared pre- and postoperatively with fundus photography. A paired samples t test was used for statistical analysis. Results: The pre- and postoperative average vertical  deviations in the primary position of 10 hypertropia patients were: 4.9△±1.0△ and 0.1△±0.3△, respectively.  The difference was statistically significant (t=19.24, P<0.001). The preoperative average amount of the V  pattern was 18.3△±3.2△, which collapsed to 1.7△±2.3△ postoperatively. The pre- and postoperative foveadisc angles (FDAs) in the group of unilateral superior oblique palsy patients were: 10.6°±4.2° and 4.4°±2.4°,  respectively. The difference was statistically significant (t=5.80, P<0.001). The pre- and postoperative  FDAs in the group of V pattern patients were: 13.1°±4.3° and 5.4°±3.4°, respectively. The pre- and postoperative average overactions of the inferior oblique were 1.5(+) ± 0.5(+) and 0.1(+) ± 0.4(+), respectively.