Tuberculous pleurisy is a relatively common form of extrapulmonary tuberculosis. To evaluate whether prednisolone treatment can prevent pleural adhesion and result in early absorption of effusion in tuberculosu pleurisy, we studied 51 cases of exudative tuberulous pleurisy patients from Dec. 51 to Aug. 1987 by prospective randomized trials. Prednisolone was administered 5㎎/㎏/day for 3 wks in the steroid group. The results obtained were as follows: 1) At 3 months after treatment, the effusion was nearly absorbed in 6 of 18(33.3%) patients of steroid group, in 4 of 33(12.2%) patients of the non steroid group, and in 10 of the total 51(19.6%) patients. 2) At 9 months after treatment, pleural adhesion above the minimal degree was observed in 17 of 33(51. 5%). patients of the steroid group, in 8 of 18(44.4%) patients of non steroid group, and in 25 of 51(49.0%) patients in total. Among those patients, severe adhesion was developed in 2 of 51(4%) patients. 3) Pleural adhesion was developed in 14 of 33(42.4%) patients of the small amount group and 11 of 18(61.1%) patients of the large amount group. 4) Pleural adhesion was developed in 7 of 15(46.4%) patients of the early treatment group(＜10 days of symptom onset), and 18 of 36(50%) patients of the late treatment group(＞10 days). In conclusion, pleural adhesion was observed in a relatively large number of patients with tuberculous pleurisy after chemotherapy. Prednisolone resulted in early absorption of fluid, but could not prevent pleural adhesion significantly.