Sixty episodes of Pneumocystis carinii pneumonia in 59 patients were evaluated for risk factors predicting fatal outcome within 14 days after bronchoscopy. We found significantly higher values for serum lactate dehydrogenase (p less than 0.001), alveolar-arterial oxygen difference (p less than 0.001) and percentage of bronchoalveolar lavage neutrophils (p less than 0.001) in patients dying within 14 days, but there was considerable overlap of these variables between the two groups. Using a score system combining the three parameters allowed however an excellent discrimination between the two groups.