In patients with ovarian cancer before they receive chemotherapy, the level of fibrin degradation products (D-dimer), is correlated with the tumor load. In this study, the evolution of D-dimer was compared in patients receiving antineoplastic therapy with the evolution of the disease. The patients could be classified into three groups. In Group 1 (nine patients), both plasma CA 125 (a tumor-associated antigen) and D-dimer remained elevated; the prognosis was always poor. In Group 2 (eight patients), CA 125 and D-dimer decreased simultaneously, complete remission was observed in two patients, and significant residual tumor was observed in the others. In Group 3 (nine patients), despite an important decrease in CA 125, D-dimer remained elevated during therapy. In this group, complete remission was observed in six patients, and three others showed a large decrease in their tumor load. The combination of a decrease in CA 125 levels with a continuous enhanced level of D-dimer during chemotherapy identified a subgroup of patients with a favorable prognosis.