OBJECTIVE To study the types of horizontal sensory strabismus, their causes, and treatment outcomes. METHODS A retrospective analysis of 44 patients with horizontal sensory strabismus who were treated from 2002 to 2007. Patients whose worse eye vision was inferior or equal to 0.2 were included. The deviation angle in primary position, causes, type of treatment, and pre-operative or post-operative diplopia were studied. A good result was considered if the final deviation was less than 10 prism diopters (pd). RESULTS Of the patients studied, 63.6% had exotropia and the 36.4% had esotropia. The visual acuity was between 0.1 and no light perception in 75% of patients. The causes responsible for low vision were congenital in 28, and acquired in 16 cases. The mean deviation was 46.7 pd. Diplopia was present in 5 cases, which were resolved with surgical treatment in 3 of them. The eye with reduced vision was operated on in 37 patients, both eyes in 6 cases, and botulinum toxin was injected in 1 case. The final outcome was successful in 90.6% of the cases which were surgically treated. The mean follow up was 31.84 months. CONCLUSIONS There were twice as many exotropias as esotropias. Strabismus surgery of the amblyopic eye shows excellent results without the need of new operations. There were no new diplopia cases.