An 8-year-old intact female West Highland White Terrier was examined for anorexia, vomiting, abdominal distension, and mild purulent vulvar discharge. The results of physical examination, laboratory testing, and radiography are presented. Emphysematous pyometra was suspected and confirmed at surgery. Clostridium perfringens was isolated from the uterine lumen. A brief discussion of emphysematous pyometra is presented.