A case of pleuropericarditis caused by Actinomyces israelli is described. The patient first underwent left upper lobectomy because of pulmonary actinomycosis. Seven months later, cardiac tamponade developed. Culture of the bloody pericardial effusion resulted in positive growth of Actinomyces israeli. He was successfully treated with penicillin G, ampicillin, and minocyclin. However, right pleural effusion appeared two months later. Cultures of the effusion again yielded positive growth of the same bacteria. However, the strain had gained resistance to any antibiotics that had been effective before. Accordingly, pleurodesis with minocyclin was undertaken, which was fortunately effective for controlling the pleural effusion.