Five tumor markers were analyzed clinically in 101 patients with borderline ovarian tumors who were treated by the Tokai Ovarian Tumor Study Group, an association comprising Nagoya University and its affiliated hospital, between January 1986 and December 1994. The positive rate of CA125 was 68.2% in serous tumor and 51.9% in mucinous tumor. The positive rate of CA19-9 was 51.5% in serous tumor and 44.7% in mucinous tumor. The positive rates and mean serum levels of CA125 in serous and mucinous tumor by stage had rising tendencies with an increase in each stage. The mean serum levels of CA19-9 in serous and mucinous tumor by stage had rising tendencies with an increase in each stage. CA125 and CA19-9 were useful for screening of borderline ovarian tumors. The positive rates of CEA and TPA in mucinous tumor were 32.5 and 27.3%, respectively, although none of the patients with serous tumor were positive in CEA and TPA. The positive rates and mean serum levels of CEA in mucinous tumor by stage had rising tendencies with an increase in each stage. The positive rate of CA72-4 was significantly lower than that of CA125 (P < 0.05).