Although cryptococcal pneumonia is a well recognized complication of the acquired immunodeficiency syndrome, optimal diagnostic approaches remain to be defined. During a 32-month period (October 1984 to June 1987), 11 patients were diagnosed with CP at our institution. The diagnosis was established in all 11 patients from specimens obtained via fiberoptic bronchoscopy (ten) and/or double-lumen catheter lavage (one). Direct stains of sedimented bronchoalveolar lavage were positive for organisms characteristic of Cryptococcus neoformans in nine of 11 patients. Transbronchial biopsies were positive (special histologic stains) in six of eight patients; bronchial washings were positive (direct smear) in seven of ten patients, the bronchial brushings were positive on stain in six of nine patients, and in one patient, a Wang transbronchial needle aspirate was positive on stain. Fungal cultures were positive on the BAL in seven of 11 patients, and on the bronchial washings in four of ten patients; the TBBx culture samples were all negative (zero of three). The serum cryptococcal antigen titer was elevated (median = 1:1024) in all eight patients in which it was assayed. Our data suggest that BAL and bronchial washings have a combined sensitivity on smear equal to that of TBBx and superior to that of TBBx fungal culture. The TBBx does not appear to be necessary in this setting. In addition, an elevated serum cryptococcal antigen titer appears to be an important adjunct in the evaluation of pulmonary infiltrates in AIDS.