An 11-yr-old female hamadryas baboon (Papio hamadryas) that died with a history of diarrhea and anorexia was submitted for necropsy. Major pathologic changes were restricted to the gastrointestinal tract. The small intestinal contents were watery and sanguinous, with a deepening of the red color in the large intestines. The intestinal mucosa was hyperemic. Microscopically, lesions consisted of surface epithelial cell necrosis in association with numerous rod-shaped bacteria and high numbers of Trichuris cynocephalus nematodes. Culturing of the small intestine yielded Clostridium perfringens. No other pathogenic bacteria were cultured using routine bacteriologic techniques. Polymerase chain reaction (PCR) analysis classified the Clostridium perfringens as type A cpb2-positive. Immunohistochemical examination with anti-β2-toxin antibodies revealed β2-toxin in close approximation with the intestinal lesions.