A multiresistant Morganella morganii subsp. morganii strain was isolated in pure culture from pneumoniclesions of a 3-week-old Belgian Blue calf, originating from a farm coping with chronic diarrhoea and respiratorytract disease as well as increased mortality in 1-3-week-old animals. Additionally, high numbers ofClostridium perfringens were isolated from the jejunum and a Giardia infection was diagnosed. Moreover,necropsy findings and histological examinations indicated nutritional myodegeneration. M. morganii is an opportunisticpathogen that is mainly associated with postoperative and nosocomial infections in immunosuppressedindividuals.