Reoperations in strabismus are done for overcorrection, undercorrections, and new strabismus problems such as dissociated vertical deviation and ptosis. Each patient requiring reoperation should be thoroughly evaluated on the basis of current findings with the understanding that some alteration in anatomy will be found. Restrictions must be freed and muscle force balanced to first provide straight eyes in the primary position and secondly the best vision possible. With persistence, 80% to 90% of patients requiring reoperation can expect a satisfactory end result.