I have made a study on the renal function in 163 cases of unilateral renal tuberculosis by examining the fluid test, indigocarmin and phenolsulfonphthalein excretion test and obtained the following results: (1) Concerning the fluid test, 46 cases (29.6%) out of 155 cases had insufficiency in excretion ability, 91 cases (58.7%) had insufficiency in concentration ability, and 46 cases (29.6%) had insufficiency both in excretion and concentration abilities. Moreover, 61 cases with insufficiency in concentration ability showed normal excretion ability, and 16 cases (10.3%) with insufficiency in excretion ability showed normal concentration ability. (2) The renal dysfuntcion in renal tuberculosis appears first in concentration then second in excretion ability. (3) In indigocarmin excretion test, 24 cases (25.8%) out of 93 cases showed disturbance in left side, 35 cases (37.6%) in right side, and 24 cases (25.8%) in both sides. (4) In phenolsulfonphthalein test, only 7 cases (8.8%) showed disturbance of excretion, i.e., excretion less than 45% in an hour, and 72 cases showed normal value, i.e., 26 cases (32.9%) with excretion over 71% and 46 cases (52.8%) with excretion between 70% and 46% in an hour. (5) The results of the previous 3 tests did not always completly coincide with each other, so the summarised dicision of the results of various examinations must be made in order to learn the renal function distinctly. (6) No difference could be found between the male and female, or the side of affection, In the research of the age of patients, the patients from 21 to 40 years old were affected more frequently but the extend of the insufficiency of renal function was rather slight.