Internal obturator and/or semitendinosus muscle flaps were used to reinforce primary appositional rectal wall repair in three dogs and one cat in this case series. All three dogs incurred rectal wall compromise during surgical excision of anal sac tumours. The cat sustained bite wounds to the perianal region resulting in abscessation and a rectal tear. Our results indicate that application of an internal obturator and/or semitendinosus muscle flap can reduce the risk of rectal wall dehiscence after primary repair, and consequently the risk of pararectal abscess or rectocutaneous fistula formation.