Although Acremonium strictum is environmentally widespread as opportunistic fungus, it may cause infection in patients who have immunodeficiency. In this study, A. strictum were isolated from the pleural fluid of a patient with colon adenocarcinoma. The patient did not receive antifungal therapy because the patient died on the same day after the isolation of the mould from the pleural fluid. Major risk factors for the fungal infection are surgery because of cancer, administration of parenteral hyperalimentation and broad-spectrum antibiotics, attaching chest tube and ventilation tube and hospitalization in intensive care unit. The minimal inhibitory concentrations (MICs) of amphotericin B, fluconazole, ketoconazole, itraconazole, voriconazole for the A. strictum strain isolated from pleural fluid were 0.125, 256, 2, 1.5 and 0.25 mu g ml(-1), respectively. In conclusion, bacteria and fungi, especially opportunistic fungi should be taken into consideration in the developing pleuritis in the patients with predisposing risks for the fungal infection.