A comparative study of 131I-hippuran renogram, 131I-hippuran excretion test and intravenous pyelogram were performed in 61 cases of gynecological cancer. The following were the results:1) Among 40 cases of cervix cancer showing normal excretory urography 7 cases (17.5%) were found to have unilateral or bilateral delayed excretory pattern on 131I-hippuran renogram and on the contrary only 2 cases (5.7%) showed a mild caliectatic change on excretory urography among 35 cases of gynecological cancer showing normal pattern of 131I-hippuran renogram. 2) In the group showing unilateral of bilateral delayed excretory pattern of 131I-hippuran renogram there was a reduction of 131I-hippuran excretion in the first 20 minutes, but there was no significant difference of 131I-hippuran excretion in 60 minutes compared with that of normal renogram group. 3) In the group showing unilateral non-functioning pattern of 131I-hippuran renogram in one side and normal pattern in the other side there was found to be no difference in 131I-hippuran excretion amount compared with that of normal renogram group. 4) It was evident from these experimental study that 131I-hippuran renogram was considered as a good examination method for the evaluation of obstructive uropathy, and if one side kidney was intact it might compensate for the other diseased kidney so far as to renal excretory function. It was also shown that the more severe the cancerous spread in the pelvic wall the more changes on 131I-hippuran renogram.