Values of CA125, CA19-9, TPA, CA72-4, BFP and LDH in sera were detected in 148 malignant ovarian tumors, 41 borderline malignant ovarian tumors, 71 benign ovarian tumors and 64 benign uterine diseases. A new cut-off value was determined by ROC graph for distinguishing malignant and borderline ovarian tumors from benign ovarian tumors. CA125 (cut off: 30 U/ml) was a highly sensitive marker for malignant and borderline malignant ovarian tumors, the value being 88.1% (52/59) and 81.8% (9/11), respectively. On the other hand, in 37 benign ovarian tumors, the positive rate was 21.6% and in 21 benign uterine diseases it was 52.4%. CA19-9 (cut off: 150 U/ml) was inferior to CA125, but it was an effective marker for mucinous ovarian tumors. TPA (cut off: 40 U/ml) was also a sensitive (84.7%, 50/59) marker of malignant ovarian tumors. CA72-4 (cut off: 4 U/ml) was a highly specific (87.0%, 60/69) marker of malignant ovarian tumors. Combination assays of CA125/CA19-9, CA125/TPA and CA125/CA72-4 were not effective. Usefulness of BFP for early malignant ovarian tumors was suggested. Seven cases of dysgerminoma showed extremely elevated LDH levels (1,248 +/- 886 IU/1/37 degrees C). Malignancy and histological type of ovarian tumors could be decided by combination assay of these tumor markers, before surgical operation.