We studied the clinical features of 59 chronic pulmonary aspergillosis cases (aspergilloma, chronic necrotizing pulmonary aspergillosis) which we experienced in our hospital. To diagnose this disease, X-rays, sputum culture and serologic tests were mainly examined, X-ray findings were a fungus ball type in 47% of cases and thickened wall of a cavity type in 32%. Positive sputum culture found was A. fumigatus 78%, A. niger 13% and A. flavus 2%. Positive rates of serologic tests showed precipitating antibody 81% and antigen 11%; 39% of beta-D glucan exceeded the reference value. As clinical symptoms, bloody sputum and hemoptysis were found at high frequency. Antifungal agents were administered intravenously or topically for treatment, primarily AMPH-B, ITCZ and MCFG. As adjuvant therapy, we administered Ulinastatin which is an elastase inhibitor for use against hemoptysis, and we performed steroid combination for cases considered to be associated with allergy. In all of 6 cases of chronic necrotizing pulmonary aspergillosis which were administered MCFG, X-ray findings improved. A pathogenic factor, elastase was isolated from Aspergillus spp., and we also found the elastase inhibitor from this series. Five of 12 strains of A. fumigatus, and one of 2 strains of A. flavus expressed elastase inhibitory activity when we screened for the culture supernatant of various Aspergillus spp. of a clinical isolate. Elastase inhibitory activity from A. niger was very weak. Culture supernatants from 5 strains of A. fumigatus and one strain of A. flavus were stable for a fever, and human leucocyte elastase was inhibited, but these did not inhibit porcine pancreas elastase. We are aiming at clinical application and plan to continue further study.