Serum levels of carcinoembryonic antigen (CEA) and cancer antigens CA 125 and CA 19.9 were determined by immunoradiometric assay in 96 patients diagnosed of invasive carcinoma of the uterine cervix and 7 patients of cervical intraepithelial neoplasia. Elevated CEA levels were found in 33%, CA 19.9 in 32%, and CA 125 in 21.5% of invasive carcinoma patients. Specificity for each tumor marker was 98%. Increased CEA and CA 19.9 levels were found in relation to clinical stage. CA 125 and CA 19.9 mean levels were significantly higher in patients with adenocarcinoma compared with squamous cell carcinoma. Detection rate of CA 19.9 in stage III adenocarcinomas was higher than in stage III squamous cell carcinoma (50 vs 21%). Sensitivity of combined antigens was also higher for adenocarcinomas increasing 60% for CA 19.9 and/or CA 125 and to 70% of cases for one of the three tumor antigens. During follow-up of cases with no evidence of disease, antigen levels showed a tendency to decrease, but all cases with progressive disease, recurrence, or metastasis were detected by elevation of one of these three tumor antigens. In conclusion, CEA, CA 125, and CA 19.9 are useful markers for detection of cervical cancer and monitorization of clinical course of disease. CA 19.9 and CA 125 have been shown to be particularly useful in patients with adenocarcinoma. © 1995 Academic Press.