To assess the use of bronchofiberscopy for the diagnosis of allergic bronchopulmonary aspergillosis (ABPA), we retrospectively analyzed bronchofiberscopic and pathologic findings of specimens obtained by bronchofiberscopy in 8 patients who met the British criteria for ABPA. Two of the 8 patients completely met Rosenberg's primary criteria for ABPA, while the remaining 6 lacked only 1 or 2 immunologic and radiographic conditions of the criteria. Bronchofiberscopic inspection revealed the presence of mucus plugs in all patients. Pathologic examination of plug specimens obtained by suction from 6 of 7 of these patients showed that the plugs consisted of allergic mucin containing fungal hyphae, diagnostic of ABPA. Bronchofiberscopy appears to be a useful tool in the diagnosis of ABPA, if immunologic and radiographic findings are not typical of ABPA. This bronchofiberscopic method is easily applicable for diagnosing allergic bronchopulmonary fungal disease (ABPFD) in addition to ABPA.