The management of advanced stage ovarian carcinomas is presently based on initial surgical debulking, multiple drug chemotherapy including cisplatinum, second-look laparotomy. Such an aggressive approach has improved objective response rates and expected survival time, but no dramatic change has been demonstrated as for definitive cure percentages. Many Authors have attempted to turn an optimal objective response to chemotherapy (no residual or minimal residual disease at second-look) into a definitive cure with irradiation. Some reports show satisfactory results, but a high incidence of bowel obstructive complications has been demonstrated, probably due to multiple surgical manipulations before radiotherapy. A reliable diagnostic tool, that could help to avoid the second-look laparotomy (whose inherent role in improving survival is not assessed) should be therefore useful. The possible role of serum tumor markers determinations, for this purpose, is here discussed on the ground of a series of 20 patients affected by stage III ovarian carcinoma. Following this experience, a valuable role seems attributable to CA 125 in monitoring tumor response. Patients achieving values under 35 U/ml before second-look laparotomy showed tumor residuals in the range O-microscopic- less than 1 cm., that is, neoplastic localizations reliable for consolidation radiation therapy.