We report a case of Aspergillus flavus pericarditis treated with fluconazole for oral candidosis. The patient with acute myeloblastic leukaemia developed tachypnoea after antileukaemic chemotherapy. Pericardial effusion was seen in the echocardiogram. Aspergillus flavus was isolated from the pericardial fluid. The patient died from aspergillosis, before the antimycotic treatment could be changed to amphotericin B.