Observation of an unusual pulmonary distribution of cryptococci in a patient at autopsy prompted a review of 36 patients with pulmonary cryptococcosis listed in the autopsy files of The Johns Hopkins Hospital. The patients ranged in age from 2 to 89 years (mean, 49 years), 19 were female, and 18 were black. All but three patients had underlying debilitating diseases, and 23 patients had received steroids and/or chemotherapy. In 25 patients (69 per cent) cryptococcosis was a major factor contributing to death, through pulmonary disease in ten, systemic involvement in seven, and central nervous system disease in eight. In 15 patients (42 per cent) cryptococcosis was diagnosed clinically. Four basic morphologic patterns were observed: 1) Seven patients (19 per cent) had one or more peripheral pulmonary granulomas. In three of these patients the granulomas were apparently quiescent, and no other lesions were found. 2) Nineteen patients (53 per cent) had what has been called granulomatous pneumonia, with intra-alveolar proliferating organisms and varying degrees of inflammatory response, which, when present, ranged from acute inflammation to diffuse intra-alveolar granulomas with giant cells. 3) In seven patients (19 per cent) organisms were present diffusely within alveolar capillaries and interstitial tissues, and reactions ranged from little or no inflammation with numerous organisms to few organisms with miliary granulomas. 4) In three patients (8 per cent) both intra-alveolar and intravascular organisms were present in massive numbers, and the primary route of infection was uncertain. Fatalities from pulmonary and generalized infection occurred in patients in each histologic group. The results show marked variability both in pathologic reaction to cryptococci and in the clinical appreciation and significance of pulmonary cryptococcosis.