To evaluate the prognostic effects of combining serum circulating tumor cells (CTCs) and squamous cell carcinoma antigen (SCC-Ag) levels on patients with locally advanced cervical cancer treated with radiotherapy. Ninety-nine patients with locally advanced cervical cancer (FIGO stage IIB-IVA) undergoing radiotherapy (RT) or concurrent chemoradiotherapy (CCRT) were identified. The association between serum CTC level and clinicopathological parameters was examined. Univariate and multivariate survival analyses were performed by using Cox's proportional hazards regression model. Elevated CTC and SCC-Ag levels were significantly associated with poor disease-free survival (DFS). Multivariate analysis suggest that serum CTC level, FIGO stage and serum SCC-Ag level were independent prognostic factors for two-year DFS. When CTC and SCC-Ag levels were combined into a new risk model to predict disease progression of cervical cancer patients, it performed a significantly better predictive efficiency compared with either biomarker alone. Serum CTC and SCC-Ag levels are potentially useful biomarkers for prediction of prognosis in locally advanced cervical cancer patients and their combination significantly improves predictive ability for survival in locally advanced cervical cancer patients.