A 5-year-old boy with chronic granulomatous disease (CCD) was treated with amphotericin B for an invasive pulmonary Aspergillus nidulans infection. The infection progressed during 6 wk of treatment despite the addition of interferon-gamma (IFN-gamma), filgrastim, and transfusions with donor granulocytes. Treatment with a novel antifungal triazole, voriconazole, resulted in an excellent clinical response.