BACKGROUND Epithelial carcinoma of the ovary has the highest death rate of any gynecologic malignancy in the developed world. The antigen CA-125 has been used over the past decade as a tumor marker for epithelial ovarian cancer and other cancers of coelomic epithelium. The object of this study was to see if the degree of elevation of preoperative CA-125 was related to length of survival in patients with epithelial ovarian carcinoma. METHODS Eighty-two consecutive patients diagnosed with epithelial ovarian carcinoma were evaluated for their initial preoperative CA-125 level, time to recurrence, length of survival and level of primary debulking as well as International Federation of Gynecologists and Obstetricians stage, grade and histology. Ovarian tumors of low malignant potential were not included in the study. All patients had their initial surgery performed by one surgeon. RESULTS Decreased length of survival was related to the degree of elevation of CA-125 prior to initial exploratory laparotomy (P = .047). The mean initial CA-125 for patients surviving five years or more (15 patients) was 899 U/mL, with an SD of +/- 1,880 U/mL, while the CA-125 for patients surviving less than five years (67 patients) was 1,978 U/mL, with an SD of +/- 1,852 U/mL (P = .02). Increased stage of disease at initial laparotomy showed a relationship to increased CA-125 (P < .0001). CONCLUSIONS In epithelial ovarian carcinoma, high preoperative serum levels of CA-125 predict decreased length of survival.