Yersinia pestis infection was diagnosed in 3 dogs. Clinical signs included lethargy (3 dogs), pyrexia (2 dogs), and a purulent skin lesion in the cervical region (2 dogs). Yersinia pestis infection is a potentially fatal zoonotic disease of human beings. Human cases have resulted from contact with infected domestic cats; however, the risk of human infection from contact with infected domestic dogs is unknown. Dogs frequently are exposed to Y pestis in areas in which there are plague epizootics; however, clinical illness in dogs is rare. In the western United States, where Yersinia pestis is endemic, plague should be considered in the differential diagnosis when examining dogs with nonspecific fever and lethargy.