Hyperfractionated radiation therapy (HF) is one of the most promising modifications of conventional fractionation (CF). However, two recent reviews on the efficacy of HF reached opposite conclusions: Stuschke and Thames (Int. J. Radiat. Oncol. Biol. Phys. 37: 259-267, 1997) concluded that the effectiveness of radiotherapy is consistently higher for HF than for CF, whereas Beck-Bornholdt et al. (Radiother. Oncol. 43: 1-21, 1997) concluded that evidence for a consistent therapeutic gain from HF is lacking and it cannot be ruled out that HF in head and neck tumors is detrimental. To clarify this issue, some important discrepancies between the two reviews are highlighted and a second look is taken at the clinical data published on HF in head and neck cancer. The most convincing prospective study so far is the EORTC trial 22791. This trial supports that HF allows escalation of the biologically effective dose to the tumor without a significant increase in late complications.