I have measured the serum bilirubin of the lungtuberculosis patients with various types. The results are as follows: (1) The total bilirubin in the healthy persons and patients having become positive to the tuberculin skin test within 6 months shows a little high level, but not efficent. (2) The total bilirubin of the lungtuberculosis patients become decreased in the severe cases and become increased in the light cases, but it's increase is not efficient. The prosperity and decay of the indirect bilirubin follows in the one of the total bilirubin, but the direct bilirubin is not observed in the most of cases and it's prosperity and decay is parallel to the one of the total bilirubin when it is observed. But it become increased in the severe cases while the total bilirubin become decreased. Because of the reverse absorption by the connection with the pathogenic changes of the liver tissue. (3) The total bilirubin become decreased in tPe gollowing cases, with active process, aggrabating symptomes, strict rest, cavity especially big cavity or maltiple cavities, remarkable body weight loosing, increased blood sedimentation rate, fever, positive bacillus in sputum, and aggravating leucocyte picture etc. (4) The total bilirubin become most decreased in the exsudative type of the mixed phthisis and the next is the productive type of it. (5) The total bilirubin of the lungtuberculosis patients with the complications especially intestinal tuberculosis shows remakably low, and it shows high in the cases with hemothorax or bloody phlegm, but it shows low in the ceses with the tendency of anemia. (6) No connections are observed between the total bilirubin and the days of illness or/and the lung function. (7) The total bilirubin is not influenced in the most of cases with the short period of various treatments, except it become decreased in the cases with the treatment of INAH and increased in the cases with the treatment of artificial pneumoperitoneum. In the cases with the longstanding administration of BAS, the total bilirubin become increased as same as the cases getting well by other treatments, but it is not changed in the cases without any changes of symptomes by the use of PAS. The direct bilirubin is not easily changed even on the cases having showed a good respondency to the treatments. (8) The prosperity and decay of the serum bilirubin is not a characteristic of the prognosis in lungtuberculosia at the present time with advanced treatments.