We have experienced 61 cases of clinically diagnosed tuberculous peripleural abscess which was surgically treated at St. Mary`s Hospital of Catholic Medical College from Mar. 1963 to Feb. 1974. Out of them, 52 cases of pathologically confirmed tuberculous peripleural abscess were reviewed and its pathogenesis, treatment and so called "rib caries" were discussed. In the past, they have been described as a variety of the names, such as rib caries, cold abscess of the chest wall, pericostal abscess, lymphadenitis tuberculosa of the chest wall, chronic draining sinuses of the chest wall and other descriptive terms. Although it has been said that the tuberculous abscess on the chest wall developed as a secondary disease from so called "rib caries" but now it has been clear that this abscess occurred not from tuberculosis of the rib but from tuberculous lesion developed between endothoracic fascia and parietal pleura usually following pulmonary tuberculosis and/or tuberculous pleurisy and the involvement of rib or ribs are secondary one from peripleural abscess, as we confirmed. Therefore we advocate that the nomination, rib caries, should not be used unless there is a primary tuberculous lesion on ribs. The results were as follows: 1. The highest age group of tuberculous peripleural abscess was ranged from the first to third decade [78%] 2. The location of tuberculous peripleural abscess on the chest wall were as follows, 31 cases on the anterior, 19 cases on lateral and 2 cases on the posterior. 3. On x-ray examination, abnormal findings including parenchymal tuberculous lesion and pleura1 changes were seen is 38 cases. 4. There was no destructive change of periosteum and rib in 23 cases of tuberculous peripleural abscess during operation. However the periosteal denudation and/or rib destruction were found in 29 cases. 5. The all cases of tuberculous peripleural abscess developed from between endothoracic fascia and parietal pleura, as we confirmed. With antituberculous therapy, operation should be radical by wide incision on the lesion including thorough curettage with proper drainage of liquified caseating materials and appropriate rib resection, if necessary.[KTCS 1975;2:159-168]