Objective To evaluate the long-term effect of sodium glycididazole （CMNa） as a hypoxic radiosensitizer on the radiotherapy for nasopharyngeal carcinoma. Methods Between May 1999 and May 2002, 211 patients with pathologically confirmed nasopharyngeal carcinoma were randomized into group- A treated by radiotherapy plus CMNa or group-B by radiotherapy alone. The staging was determined according to 92＇ Fuzhou staging systerm. The type, procession and dosage of radiotherapy were identical in both groups. The early adverse effect grade was assessed based on the CTC2.0 criteria and the late adverse effects were evaluated according to the RTOG/EORTC criteria. The median follow-up time was 52 months. All the data was analyzed by the SPSS 13.0 software. Characteristics and adverse events of these patients were compared between the two groups using t-test and the Wilcoxin rank sum test. Time-to-event curves were estimated using the Kaplan-Meier method. The prognostic parameters were analyzed using univariate analysis and the Cox multivariate regression analysis. Results The clinical data of the two groups were comparable. The 3-year survival was 88.4% in group-A , while 75.2% in group-B, with a statistically significant difference between two groups（P = 0. 010）. Univariate analysis showed that the 3-year survival was statistically correlated with N-staging （ N（0-1）86. 9%, N（2-3） 73.8%, P 〈 0. 001 ）, T-staging （ T（1-2） 85.6%, T（3 -4） 79.3% , P = 0. 014 ）, TNM staging （ P = 0. 039 ）, and whether using CMNa or not during rediotherapy（ Group-A 88.4%, Group-B 75.2%, P = 0.010 ）. The 5-year recurrence-free survival, 5-year metastasis-free survival and 5-year overall survival were 75.8% , 74.9% and 77.7% in Group-A, while 63.0%, 63. 0% and 62. 4% in Group-B with a statistically significant difference between two groups （0. 013,0.022 and 0.010, respectively）. If stratified in the subgroups, the overall survival of stage Ⅲ-Ⅳ patients was statistically different between group A and B（ P = 0.009）, however, not of stage Ⅰ-Ⅱ patients （P=0. 502）. Cox multivariate regression analysis showed that the independent prognostic parameters for survival were N-stage（RR =3. 288） , T-stage（ RR = 2. 147） and use of CMNa during rediotherapy （ RR = 0.407）. However, there was no statistically significant difference between two groups in acute or late adverse effects on nervous system or heart, which suggested that use of CMNa during radiotherapy would not aggravate the toxicity caused by radiotherapy. Condusion Sodium glycididazole is well tolerable effective as a hypoxic radiosensitizer, which can improve the efficacy of radiotherapy and the long-term result of nasopharyngeal carcinoma patients, especially for the stage Ⅲ-Ⅳ patients.