The objective of this study was to investigate the prognostic significance of the hemoglobin (Hb) levels at different timepoints in locally advanced squamous cell carcinoma of the head and neck (SCCHN). Included were 111 patients. The hemoglobin levels were assessed before surgery (PreS-Hb), between surgery and radiotherapy (HbAAC), before postoperative radiotherapy (PreRT-Hb) and at the end of radiotherapy (EndRT-Hb). HbAAC takes into account the duration of anemia during the interval between surgery and radiotherapy. Higher HbAAC corresponds with lower Hb levels. Five year locoregional control (LRC) among patients with HbAAC > or = median was 72% and significantly worse as compared to the 88% in case of HbAAC < median (p = 0.0097). Multivariate analysis for LRC showed that the HbAAC was a prognostic factor. Overall survival (OS) after 3 years was 77% in case of HbAAC < median and 34% in case of HbAAC > or = median (p < 0.0002). Multivariate analysis for OS showed that the PreS-Hb and HbAAC were prognostic factors. Hb level between surgery and radiotherapy is an important prognostic factor for both LRC and OS among patients with SCCHN treated with surgery and postoperative radiotherapy.