Twelve patients with aspergilloma were treated with intracavitary or endobronchial administration of antifungals. Patients with successful therapy had significantly shorter mean duration of the disease course (3.6 months) than the less effective group (44.4 months, p < 0.01). Minimal inhibitory concentrations of antifungal agents against isolated strains of aspergilli were considerably lower than estimated intracavitary concentrations of the antifungals. A pathologic examination suggested that the old mycetoma was for the most part comprised of dead mycelial cells, against which antifungal agents were not effective. However, clinical improvement was obtained, regardless of the roentgenographic improvement. Our study suggested that early diagnosis and therapy are recommended to achieve better therapeutic effect.