Objective To prospectively assess the influence of intensity-modulated radiotherapy (IMRT) and conventional radiotherapy on quality of life (QOL) in patients with head and neck cancer (HNC) for clinical guidance. Methods From May 2007 to May 2008, 102 HNC patients were enrolled in this study. Fifty-two patients were treated with IMRT and 50 with conventional radiotherapy. In patients with IMRT, at least one parotid gland was spared, and the contralateral submandibular gland was spared in 24 patients. The parotid and submandibular gland were not spared in patient with conventional radiotherapy.QOL was assessed using EORTC QLQ C30 and HN35 questionnaires at 4 time points (before radiotherapy,end of radiotherapy, 2 months and 6 months after radiotherapy). A change of 10% in scores of the instru-ment range had been previously demonstrated to be clinically significant. Results In the study, 94% (31/33) of the QOL domains were worse after IMRT or conventional radiotherapy, including 49% (16/33) with significant difference (U=2.72-5.98, all values of P<0.01) and 33% (11/33) with clinical signifi-cance. At 2 months after radiotherapy, 12% (4/33) of the domains showed clinically significant improve-ment, however, 15% (5/33) of the domains did not show any improvement (U=3.10-5.93,all value of P < 0.01). Continuous improvement in most domains of QOL was shown at 6 months after radiotherapy. Clini-cally and statistically significant improvement were shown in 21% (7/33) of the domains, and some were even better than pretreatment except in dry mouth and sticky saliva scales (U=4.49 , P<0.01 and U=4.87 ,P <0.01). Compared with conventional radiotherapy, the dry mouth and sticky saliva caused by IM-RT were milder (U=4.57,P <0.01 and U=5.57, P < 0.01) and continuous improvement were shown over time after radiotherapy (U=7.23, P <0.01 and U = 7.57, P < 0.01). Similar improvement weren't shown in patients with conventional radiotherapy. Conclusions QOL in HNC patients is significant worse after ra-diotherapy. QOL can be improved continuously over time after treatment except dry mouth and sticky saliva which are the main factors affecting QOL. IMBT, causing less dry mouth and sticky saliva when compared with conventional radiotherapy, has benefits for the preservation of QOL.