Objectives/Hypothesis To review toxicity and outcomes in patients with head and neck cancer treated with simultaneous integrated boost–intensity‐modulated radiotherapy (SIB‐IMRT). Study Design Review of experience with the SIB‐IMRT technique. Methods Fifty patients were treated with the SIB‐IMRT technique. Two possible schedules of radiation therapy (RT) were used: SIB 70 (70/60/54 in 33 fractions) and SIB 66 (66/60/54 in 33 fractions). Forty‐one patients also received chemotherapy. Results All but two patients completed treatment as prescribed. No G4 acute toxicity has been reported in our series. We did not observe any G3 to G4 chronic toxicity, apart from one case of cutaneous necrosis. After a median follow‐up of 23.3 months (range, 1–60 months), 41 patients (82%) were alive and negative for disease, and one patient (2%) was alive with distant metastases. Eight patients (16%) died, seven because of progressive disease and one for other causes. Conclusions SIB‐IMRT is a highly effective and safe technique of RT in the treatment of head and neck cancer. Level of Evidence 4 Laryngoscope, 123:E97–E103, 2013