The importance of the overall treatment time (OTT) has a paradoxical status in the current era of concomitant chemoradiotherapy. The main objective of this nationwide study was to evaluate the correlation between overall treatment duration and clinical outcome in cervical cancer patients treated primarily with curative concurrent chemoradiotherapy (CCRT). In this population-based cohort study, 2,594 patients diagnosed with International Federation of Gynecology and Obstetrics (FIGO) stage I-IVA uterine cervical cancer were studied. Univariate and multivariate analyses of prognostic factors were analyzed using Cox's proportional hazards models. The median irradiation duration was 59 days. Significant prognostic factors related to poor cancer-specific survival (CSS) and overall survival (OS) included old age, nonsquamous cell cancer type, high-grade histology, increased tumor size, advanced FIGO stage, and prolonged OTT. After multivariate analysis, prolonged treatment time remained as a significant factor for poor CSS (hazard ratio, HR = 1.33; p < 0.001) and OS (HR = 1.15; p = 0.05). Further subgroup analysis showed that the 5-year OS rates after a treatment time of ≤ 56 days compared with > 56 days in patients with FIGO stages I-IIB and III-IVA were 70% and 65% (p = 0.002) compared with 43% and 42% (p = 0.67), respectively. Inconclusion, completion of CCRT within 8 weeks is recommended, particularly for patients with FIGO stage I-IIB disease.