Background: The purpose of this observational study was to evaluate the prognostic significance of the pre-treatment plasma fibrinogen level for survival outcomes in nasopharyngeal carcinoma (NPC). Methods: A total of 998 patients with NPC treated at a single centre in China were retrospectively enrolled, of whom 182 (18.2%) developed distant metastasis during follow-up. Survival analyses were performed by the Kaplan-Meier method and Cox regression modelling to measure 3-year overall survival (OS) and distant metastasis-free survival (DMFS). Results: Median OS for the entire cohort was 37.8 months. Using the cut-off value of 3.345 g/L identified in receiver operating curve analysis for fibrinogen, a high pre-treatment plasma fibrinogen level were associated with older age (P = 0.034), advanced TNM stage (P = 0.004) and development of distant metastasis (P < 0.001; Chi-square test). Multivariate Cox proportional hazard analysis demonstrated the pre-treatment plasma fibrinogen level was an independent significant prognostic factor for OS and DMFS in both the entire cohort and also among patients who developed distant metastasis during follow-up. Conclusions: This study suggests the pre-treatment plasma fibrinogen level may serve as an independent prognostic marker to predict the survival outcomes of patients with NPC, including patients with metastatic disease.