These two pulmonary actinomycosis cases had undergone right upper lobectomy and left lower lobectomy individually under the diagnosis of lung cancer and lung abscess. Recently pulmonary actinomycosis is very rare by the widespread use of antibiotics. In addition to clinical similarity to lung cancer and pulmonary tuberculosis, lack of suspicion and difficulty in obtaining adequate culture material also hamper the precise preoperative diagnosis. The purpose of this report is to review of our experiences and to enhance consideration of pulmonary actinomycosis.