It has been known that the pulmonary mycosis generally results from saphrophytic colonization of pre-existing lung cavities, e.g. , due to pulmonary tuberculosis, abscess, bronchiectasis. or congen-ital cysts. Recently, the authors experienced four cases of the pulmonary mycosis which were all treated surgically, and in our opinion, three of them were considered to arise from secondary saphrophytic colonization of pre-existing tuberculous cavities by serial chest roentgenograms. One of them was actinomycosis which was known as relatively rare pulmonary mycosis, and its clinical experience was previously reported. The purpose of this report is mainly to review our clinical experience and some related literatures with three patients with aspergillosis. Many writers have stressed the sputum culture for aspergillus, immunologic study and serial roentgenographic findings were all important or essential in diagnosing aspergillosis. Surgical resection appears to be the treatment of choice for the mycosis of lung, and systemic administration of effective anti-fungal agents such as amphotericin B for aspergillosis and penicillin for actinomycosis respectively following surgical intervention is usually necessary to eradicate completely.[KTCS 1973;1:29-36]