BACKGROUND Pulmonary sporotrichosis is a rare event. Sporothrix schenckii is a dimorphic fungus and develops at 37 degrees C in yeast form. Usually hyphae are not observed in tissues, although their presence has been occasionally demonstrated in biopsies. CASE A 37-year-old man, human immunodeficiency virus-1 positive, with a CD4 cell count of 345/mm3, developed a productive cough. A sputum smear revealed the presence of a large amount of long, thin, septated micelia. The hyphae bore oval, sessile conidia. Cultures of sputum yielded numerous colonies of S schenckii. CONCLUSION This is the first report of hyphae of S schenckii in sputum. This case emphasizes the possibilities of cytology for the diagnosis of mycotic infections. Fungi have typical morphologies, and it is possible, on the basis of microscopic evidence, to suspect the nature of the infection early and thus to direct culture procedures.