A 9 year old male intact Boston Terrier presented to the Cornell University Hospital for Animals Soft Tissue Surgery Service with a 1.5 month history of tenesmus and a swelling lateral to the anus. The primary veterinarian had diagnosed a left-sided perineal hernia and referred the owner to Cornell for evaluation and possible surgical repair. Digital palpation per rectum revealed a left-sided perineal hernia. Physical examination revealed a Grade III/VI left-sided heart murmur, which was further investigated by the Cardiology Service. Echocardiography revealed bilateral myxomatous valvular degeneration with mild to moderate mitral valve regurgitation. Doppler blood pressure revealed hypertension. The patient was anesthetized and a herniorrhaphy was performed using the internal obturator muscle transposition technique. The patient was castrated in a routine pre-scrotal fashion. He recovered uneventfully and was discharge with pain medications and amlodipine to manage his hypertension.