The serum levels of CYFRA 21.1, CEA and SCC were prospectively determined in 156 patients diagnosed with carcinoma of the uterine cervix from 1995 to 2003. Histology revealed squamous cancer in 119 patients, adenocarcinoma in 25 patients and adenosquamous carcinoma in the remaining 12 patients. We considered 3.3 ng/ml, 5 ng/ml and 2 ng/ml as the upper limits of normality for CYFRA 21.1, CEA and SCC, respectively. The sensitivity of CYFRA 21.1, CEA and SCC was 26%, 25% and 43%, respectively, at diagnosis. SCC was clearly related to tumor histology, with significantly higher levels in squamous tumors than in other histological types (p<0.0001). The relationship of CEA with the histological type was poor, but the highest concentrations were found in adenocarcinomas (p=0.034). All the tumor markers were related to well known prognostic factors such as tumor size, tumor stage, parametrial invasion and nodal involvement. Abnormal pretreatment serum levels indicated a high probability (>83%) of parametrial invasion in squamous tumors. Likewise, pretreatment SCC and CYFRA 21.1 serum levels were of prognostic value, with a shorter DFS and OS in patients with abnormal levels. Multivariate analysis indicated that stage, histological grade and parametrial invasion were independent prognostic factors, but not tumor markers. In conclusion, SCC is the tumor marker of choice in squamous tumors and the addition of CEA or CYFRA 21.1 does not significantly increase the sensitivity obtained by using SCC alone.