From 1966 through 1977, 52 patients with primary invasive epithelial carcinomas of the ovary were treated at the University of Kentucky Medical Center with exploratory laparotomy and debulking of tumor, followed by chemotherapy using a single alkylating agent. Stage of disease, degree of histologic differentiation, cell type, and amount of residual tumor after surgery were all related to patient survival. The findings of this study suggest that excellent survival can be expected when single akylating agent therapy is used in patients who have well-differentiated, early stage ovarian tumors completely excised at the time of primary surgery. A high-risk population of patients is also identified in whom primary combination chemotherapy is indicated. This high-risk group includes those patients with: (1) poorly differentiated tumors; (2) significant (>2 cm in diameter) residual tumor following surgical debulking or; (3) advanced stage (III or IV) disease.