A case of pulmonary infection caused by Trichosporon beigelii is reported. The infection occurred in a neutropenic patient with acute lymphoblastic leukemia. His chest radiograph showed a 6-cm pulmonary infiltrate in the right midzone and an apical infiltrate on the left. Repeated cultures of bronchoalveolar lavage grew budding yeast that was identified as T beigelii on the basis of morphological, cultural, and biochemical characteristics. He responded to amphotericin-B therapy. Systemic infections caused by this yeast are rare and its causal relationship in localized lung disease has been reported only seven times previously.