Objective To observe the effect of residual tumor after radiotherapy on survival rate of patients with nasopharyngeal carcinoma (NPC). Methods From Jan. 1989 to Dec. 1998, 108 of 304 NPC patients pathologically confirmed, had residual tumor after radical radiotherapy, of whom, 26, 68, 14 had residual lesion in the nasopharyngeal cavity alone, cervical lymph node alone, and nasopharyngeal cavity plus cervical lymph node. Results The overall 1 , 3 , 5 , and 10 year survival rates (OS) significantly decreased in the residual group. The highest OS was in the group with nasopharynx residual alone, and the lowest in nasopharynx plus residual lymph node group. The bigger the residual lesion, the lower the OS. Conclusions The overall survival rate decreases in patients with residual lesion after radiotherapy, especially in patients with both nasophrynx and regional lymph node residual. Tumor residual after radiotherapy can be a prognostic indicator for patients with NPC.