AIM:To observe the effect of binocular or monocular medial rectus muscle resection in treatment of convergence insufficiency concomitant exotropia,sometimes lateral rectus muscles recession might be needed.METHODS:The selected 181 patients were performed binocular or monocular medial rectus muscle resection,sometimes might be associated with lateral rectus muscles recession.General ophthalmological examination,strabismometry,ocular movement and synoptophore were performed preoperation,1 week,2 months and 6 months postoperation.RESULTS:The orthotopic possibility were 80.1% after 1 week of operation,83.7% after 2 months of operation and 81.3% after 6 months of operation.The squint of post-operation had significant difference compared with that of preoperation(P<0.01).There was no significant difference between preoperation and postoperation with that of binocular visual functional restoration(P>0.05).CONCLUSION:Binocular or monocular medial rectus muscle resection in treatment of convergence insufficiency concomitant exotropia has satisfactory effect.