This report describes two patients with acquired immune deficiency syndrome (AIDS) in whom respiratory failure and opportunistic infection associated with secondary alveolar proteinosis developed. In one patient, the alveolar proteinosis was apparently secondary to Mycobacterium tuberculosis and in the other to Pneumocystis carinii and cytomegalovirus infection. Both patients died of respiratory failure, and it was suspected that secondary alveolar proteinosis could have been a contributing cause of death.