|A 4-year-old intact female Maltese was referred to the Animal Medical Center of Chonbuk National University with a history of consistent fecal incontinence over 4 months following sacculectomy surgery. We suspected that anal sacculectomy resulted in loss of the external anal sphincter. On physical examination, the external anal sphincter muscle on the left side was intact, while the external anal sphincter muscle on the right side could not be detected and exhibited severe laceration. To repair the defect, the left semitendinosus muscle was transposed around the anus. The left semitendinosus muscle was isolated and transected near the stifle, reflected dorsally and passed around the ventral rectum into the pararectal fossa. Care was taken to preserve the integrity of the vasculature and nerve supply. The muscle was secured dorsally with simple interrupted sutures to the levator ani and coccygeus muscles to simulate the external anal sphincter. Nine days after surgery, the dog was defecating normally with no evidence of incontinence. The use of semitendinosus muscle flaps is a good option for the treatment of fecal incontinence secondary to loss of sphincter muscle in dogs.