In this case series study, we assessed the effects of recession-resection surgery augmented with botulinum toxin A chemodenervation for patients with chronic paralytic horizontal strabismus. In addition, we compared these effects with those of full tendon transposition (FTT) augmented with posterior intermuscular suture (PIMS). Ten patients who underwent strabismus surgery due to paralytic horizontal strabismus were retrospectively reviewed. They received a recession-resection surgery augmented with botulinum toxin A chemodenervation (type I surgery) or a FTT augmented with PIMS (type II surgery). The preoperative angle of deviation (AOD) and postoperative improvement in AOD were compared according to the type of procedure. The preoperative AOD was 60.00 ± 28.50 prism diopters (PD) for type I surgery and 68.00 ± 27.06 PD for type II (p = 0.421). Improvement in AOD was 53.20 ± 25.01 PD for type I surgery and 44.20 ± 18.74 PD for type II (p = 0.548). Recession-resection surgery augmented with botulinum toxin A chemodenervation is a concise and effective procedure for treating paralytic horizontal strabismus.