The records of 31 cats and eight dogs undergoing surgical correction of peritoneopericardial diaphragmatic hernia (PPDH) from 2000 through 2007 were reviewed. Weimaraners and long-haired cats of varying breeds, particularly Maine Coon cats, appear to be at higher risk of PPDH. Presenting complaints were most commonly related to the respiratory and gastrointestinal tracts in both dogs and cats, although respiratory signs were more prevalent in cats, and gastrointestinal signs were more common in dogs. The most common herniated organs were liver, gallbladder, and small intestine. Mortality associated with surgical repair of PPDH in cats and dogs was low in the first 2 weeks postoperatively, and prognosis for return to normal function was excellent. Peri-and postoperative complications were typically minor and self-limiting.