OBJECTIVE: In Germany, as in many other countries, nationwide data on mortality attributable to diagnosed diabetes are not available. This study estimated the absolute number of excess deaths associated with diabetes (all types) and type 2 diabetes in Germany. RESEARCH DESIGN AND METHODS: A prevalence approach that included nationwide routine data from 64.9 million people insured in the German statutory health insurance system in 2010 was used for the calculation. Because nationwide data on diabetes mortality are lacking in Germany, the mortality rate ratio from the Danish National Diabetes Register was used. The absolute number of excess deaths associated with diabetes was calculated as the number of deaths due to diabetes minus the number of deaths due to diabetes with a mortality that was as high as in the population without diabetes. Furthermore, the mortality population-attributable fraction was calculated. RESULTS: A total of 174,627 excess deaths were due to diabetes in 2010, including 137,950 due to type 2 diabetes. Overall, 21% of all deaths in Germany were attributable to diabetes and 16% were attributable to type 2 diabetes. Most of the excess deaths (34% each) occurred in the 70- to 89-year-old age-group. CONCLUSIONS: In this first nationwide calculation of excess deaths related to diabetes in Germany, the results suggest that the official German estimates that rely on information from death certificates are grossly underestimated. Countries without national cohorts or diabetes registries could easily use this method to estimate the number of excess deaths due to diabetes.