Mycobacterium avium paratuberculosis (Map) was cultured from the feces of a wild-caught, female, adult Southern black rhinoceros. The animal, which presented with a 4-mo history of diarrhea and weight loss, was prescribed a course of antimycobacterial drugs. The clinical signs resolved, and the feces were repeatedly culture negative thereafter. Although the Rhinocerotidae are likely to be resistant to Johne's disease, this case raises the possibility that they can become transiently infected with the causative organism.