Abstract: Background: Intensity modulated radiotherapy (IMRT) is still a standard of care for radiotherapy in locally advanced head and neck cancer (LA-HNSCC). Simultaneous integrated boost (SIB) and moderate hypofractionation offer an opportunity for individual dose painting and a reduction in overall treatment time. We present retrospective data on toxicity and locore-gional control of a patient cohort with LA-HNSCC treated with an IMRT-SIB concept in compar-ison to normofractionated 3D-conformal radiotherapy (3D-RT) after a long-term follow-up. Methods: Between 2012 and 2014, n=67 patients with HNSCC (stages III/IV without distant me-tastases) were treated with IMRT-SIB either definitively (single/total doses: 2.2/66 Gy, 2.08/62.4 Gy, 1.8/54 Gy in 30 fractions) or in the postoperative setting (2.08/62.4 Gy, 1.92/57.6 Gy, 1.8/54 Gy). These patients' clinical courses were matched (for sex, primary, and treatment concept) as part of a matched-pair analysis with patients treated before mid-2012 with normofractionated 3D-CRT (definitive: 2/50 Gy followed by a sequential boost up to 70 Gy; postoperative: 2/60-64 Gy). Chemotherapy/ immunotherapy was given concomitantly in both groups in the definitive situation (postoperative dependent on risk factors). The primary endpoints were acute and late toxicity; the secondary endpoint was locoregional control (LRC). Results: Sixty-seven patients treated with IMRT-SIB (n = 20 definitive, n = 47 adjuvant) were matched with 67 patients treated with 3D-RT. There were minor imbalances between the groups concerning nonmatching variables such as extracapsular extension (ECE) and chemotherapy in IMRT-SIB. Significantly less toxicity was found in favor of IMRT-SIB concerning dysphagia, ra-diation dermatitis, xerostomia, fibrosis, and lymphedema. After a median follow-up of 63 months, the median LRC was not reached (IMRT-SIB) vs. 69.5 months (3D-RT) (p=0.63). Conclusions: This moderately hypofractionated IMRT-SIB concept was shown to be feasible with less toxicity than conventional 3D-RT in this long-term follow-up observation.