The purpose of this study is to know and compare the changes in plasma proteins in normal pregnancy with those in gynecological malignancies. The results obtained are as follows. Factor VIII activity continued to increase during pregnancy and reached about 200%. It also continued to increase and showed a high level (250-300%) in malignancy, in advanced stages. At III activity increased in the first trimester and showed reached a normal level after 28 weeks of gestation. It decreased on the third day of puerperium and recovered to normal 1 month after delivery. At III activity decreased only in the end stage of malignancy. Factor XIII activity continued to decrease and was 50-60% during the second and third trimester. It began to recover at the third day of puerperium and completely recovered at 1 month after delivery. Factor XIII activity also continued to decrease and was at a low level (33.8-51%) in advanced stages. Plasminogen activity increased from the first trimester and was 120-130% during the second and third trimesters and after delivery. In malignancy, it did not show any remarkable change. alpha 2-PI activity moderately increased in the first trimester, but was at a normal level during the second and the third trimester. It increased slightly on the third day of the puerperium and recovered to normal 1 month after delivery. alpha 2-PI activity showed no remarkable change in malignancy, but decreased in some advanced cases. HRG began to decrease from the second trimester and was 46.5% at the end of the third trimester. In the puerperium, HRG began to recover on the third day and reached normal at 1 month. HRG showed a low titer in advanced stages of malignancy. Sialic acid increased constantly during pregnancy, but it was within the normal range. On the third day of puerperium, it reached 72.3mg/dl. Sialic acid showed a high level with in advanced stages of malignancy. IAP did not change during pregnancy. It showed a slight increase on the third day after delivery, but it was within the normal range. Malignancy showed a high level of HRG with in advanced stages. CIG was normal during and after pregnancy. In cervical carcinoma, CIG increased at in Ib, II and cervical carcinoma. Ovarian carcinoma did not show any change.