Objective: The present study was aimed at analyzing the impact of enteral nutrition on the maintenance of body weight and on the necessity of replanning and/or interruption of treatment of head and neck cancer patients undergoing intensity-modulated radiotherapy (IMRT). Materials and Methods: Cases of patients submitted to IMRT in the period from January 2005 to October 2008 were retrospectively reviewed, and 83 of them were included in the study. Results: Median patients’ age was 58.6 years. Only five patients (6%) had their treatment interrupted for a period ranging from 4 to 18 days, and in 19 cases (23%) required replanning. Enteral nutrition was initiated before the radiotherapy in 16 patients (19%). Weight loss of > 5% was observed in 58 patients (70%), with a higher prevalence in the group of patients who had not received pre-radiotherapy enteral nutrition. No significant difference was observed between the groups regarding the necessity of radiotherapy replanning (25% versus 21%; p = 0.741) and necessity and duration of treatment interruption. Conclusion: Enteral nutrition is of a great value in the body weight maintenance, but no benefit was observed with the performance of endoscopic percutaneous gastrostomy as compared with radiotherapy interruption/replanning.