The usefulness, limitations, and problems of tumor markers in primary and secondary screening for ovarian cancer were evaluated and the following conclusions were drawn : 1. When CA125 is used singly in the screening, one should be aware that its level is significantly reduced when the patient is over the age of 50. Therefore a cut-off level should be set, depending on patient's age. Becuase the CA125 level rises significantly during menstruation, this period should be avoided when scheduling blood sample collection. CA125 has a high false-positive rate in endometrial cyst or mature teratoma of ovary. 2. The detection rate of ovarian cancer at screening is approximately 0.02%. The positivity obtained by CAMPAS (computer aided multivariate and pattern analysis system) at the primary screening is 0.68% ; and ovarian cancer is found in about 3% of these CAMPAS-positive individuals. Therefore those patients with a high risk can be effectively detected at the primary screening by CAMPAS. However, because there still is a risk of overlooking 20% of the patients with stage I cancer, further improvement is required for practical application of CAMPAS. Furthermore it is extremely difficult to distinguish borderline malignant ovarian tumors from benign tumors by tumor markers (including CAMPAS) alone. 3. The sensitivity and specificity in the secondary screening can be improved by using CAMPAS combined with CA546 and GAT. The primary screening of ovarian cancer with tumor markers alone is associated with a high risk of overlooking some and is not practical at this moment. However, using a system that incorporates statistical methods (such as CAMPAS) is highly promising in the secondary screening, which is intended to differentiate between benign and malignant tumors.