Pittsburgh Pneumonia Agent, Legionella micdadei, is a recently recognized source of pulmonary infection in immunocompromised hosts. A literature review suggests a typical pattern of clinical and radiologic presentation, of which the following case is representative. Eighteen of twenty-one infections have occurred in recipients of cadaveric renal transplants, defining a population at risk. The onset often occurred within days to weeks of bolus doses of corticosteroids. Fever, often accompanied by mild pulmonary symptoms usually developed, coupled with nodular or segmental chest infiltrates which were often well defined or rapidly expansile. Recognition of this pattern followed by prompt open lung biopsy may lead to increased survival.