Abstract: Objective To detect the expressions of cyclooxygenase-2 (COX-2) and basic fibroblast growth factor (bFGF) and evaluate their value in predicting the radiotherapy sensitivity in nasopharyngeal carcinoma (NPC). Methods The expressions of COX-2 and bFGF were detected immunohistochemically in biopsy samples of NPC, and their relationship with the radiotherapy sensitivity of the tumors were analyzed. Results In 97 NPC cases, the positivity rates of COX-2 and bFGF were 71.1% (69/97) and 64.9% (63/97), respectively. Correlation analysis demonstrated that a positive COX-2 expression was positively correlated with an advanced T status and N status, and bFGF expression was positively associated with an advanced N status in NPCs. In radiotherapy-sensitive and radiotherapy-insensitive cases, the positive rate of COX-2 was 62.8% and 92.6%, and that of bFGF was 57.1% and 85.2%, respectively. The expression of COX-2 was positively correlated with that of bFGF (r=0.486, P<0.05). The radiotherapy sensitivity differed significantly among patients with different statuses of COX-2 and bFGF positivity. Conclusion COX-2 and bFGF can be effective and sensitive biomarkers for predicting radiotherapy sensitivity in NPC.