In the 10 years from 1958 through 1968, 23 patients have undergone 24 times of operation for constrictive pericarditis at this department. Follow-up data were available for periods varying several months to almost 10 years from examination at this department or follow-up letters. There were 21 males and 2 females in this series. Range of the age varied from 2 years to 53 years. Seven cases were below 15 years of age. There were two hospital death, one expired two weeks and another four weeks after the pericardiectomy. In both of them, myocardial damage by disease process seemed to be major contributing factors. Clinical and histological study showed tuberculous origin in 12 cases, non-specific chronic infiammatory changes in 8 cases and in 3 cases previous pyogenic pericardial infection by staphylococcus preceded to the constriction. In 11 cases bone tissue was noted microscopically in the pericardium: Sixteen patients[70 %]had pleural effusions, five cases had bilateral, 6 right, and 5 left. Calcification was seen along cardiac border in 9 cases. In 15 catheterized patients, 6 showed pressure gradients between vena cava and right atrium, ranging from 6 mmHg to 10 mmHg. One case was reoperated 3 months after the original operation resulting in marked improvement. In this reoperated case the original pericardiectomy seemed to be incomplete. In 21 cases. excluding 2 hospital death, symptoms and physical findings improved markedly in every patient[KTCS 1968;1:61-68]