Context: Retrospective studies have demonstrated that the use of positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) in the posttherapy evaluation of patients with cervical carcinoma is predictive of survival outcome. Objective: To validate the association between the metabolic response on the 3-month posttherapy FDG-PET and long-term survival outcome. Design, Setting, and Patients: A prospective cohort study designed to validate our previous finding that the results of a 3-month posttherapy FDG-PET are predictive of long-term clinical outcome. A total of 92 women were treated with external irradiation, brachytherapy, and concurrent chemotherapy from January 2003 through September 2006. Posttherapy whole-body FDG-PET was performed 2 to 4 months (mean, 3 months) after completion of therapy. Main Outcome Measures: The primary outcome end points were metabolic response, progression-free survival, and cause-specific survival. Results: Posttherapy FDG-PET showed a complete metabolic response in 65 patients (70%), a partial metabolic response in 15 (16%), and progressive disease in 12 (13%). Their 3-year progression-free survival rates were 78%, 33%, and0%, respectively (P<.001). Multivariate analysis demonstrated that the hazard ratio (HR) for risk of recurrence based on the posttherapy metabolic response showing progressive disease was 32.57 (95% confidence interval [CI], 10.22-103.82). A partial metabolic response had an HR of 6.30 (95% CI, 2.73-14.56). These were more predictive of survival outcome than the pretreatment lymph node status (HR, 3.54; 95% CI, 1.54-8.09). Conclusion: In this single-site study population of women with cervical cancer, 3-month posttherapy FDG uptake, as detected by whole-body PET, was predictive of survival.