Pulmonary cryptosporidiosis is a rare complication of intestinal cryptosporidiosis in AIDS patients. We report the epidemiological, clinical, radiological, microbiological and immunological findings in 5 AIDS patients with pulmonary cryptosporidiosis. Diagnosis was based on the detection of acid-fast oocysts in sputum or aspirated bronchial material using the Kinyoun technique. Microbiology laboratories should be alert to the possibility of Cryptosporidium spp oocysts presence in respiratory specimens from patients with advanced HIV/AIDS disease and pulmonary involvement.