Invasive aspergillosis is an increasing problem in patients with acute leukaemia, bone marrow transplantation, immunosuppression after solid organ transplantation, or acquired immunodeficiency syndrome. Despite available antifungal treatment, the mortality approaches 100% in patients with dissemination of the infection into the central nervous system (CNS). Using a novel triazole, voriconazole, we successfully treated an Aspergillus brain abscess in a patient with acute leukaemia. Drug levels above the minimal fungicidal concentration for Aspergillus species were detected in cerebrospinal fluid (CSF) specimens, and the treatment achieved an objective response.