Background. Data on in-hospital MR (IHMR) of head and neck cancer (HNC) are sparse. Methods. IHMR was determined in Germany between 2005 and 2018 using nationwide population-based diagnosis-related group (DRG) data of 1,090,596 HNC. Results. The overall average IHMR was 0.04 ± 0.02 . IHMR increased with older age to 0.04 ± 0.01 for patients of 65-79 years of age (relative risk [RR] in relation to patients of 35-49 years of age = 1.767 ; 95 % confidence interval CI = 1.040 to3.001) to a maximum of 0.07 ± 0.01 for patients of 80 years and older ( RR = 2.826 ; CI = 1.663 to 4.803). IHMR was the highest when no HNC-specific treatment, i.e., best supportive and palliative care, was applied ( 0.11 ± 0.01 ; RR in relation to tumor biopsy surgery = 7.241 ; CI = 3.447 to 5.211). IHMR was not different between surgery, radiotherapy, or chemotherapy/biologicals. Conclusions. IHMR did not change over time. Efforts are needed to decrease the IHMR for HNC.