OBJECTIVES: In Germany, regional data on diabetes prevalence are scarce. Robust regional prevalence estimates are required for allocating limited health care resources appropriately. The aim of this study was to determine the regional diabetes prevalence in Germany for 2011 and 2022. METHODS: A large database containing 80 percent of all prescriptions redeemed in German pharmacies and accounted by the statutory health insurance (SHI) was analyzed. By defining a prescription filter for anti-diabetic agents, the numbers of drug treated diabetic patients in different age and sex groups were estimated for all 16 federal states in Germany. A multiple linear regression model was used to adjust the values to the whole SHI population with the help of an additional database containing exhaustive drug sales data. Crude prevalence was calculated using SHI member statistics. By using population data of the federal statistical office, age- and sex-standardized prevalences for 2011 were estimated and projected to the year 2022. RESULTS: In total, 5809403 patients were found for 2011, which means a crude prevalence of 8.38% (standardized: 8.18%) for Germany. The highest prevalence was found in the East German state Saxony-Anhalt with 12.74% (12.13%), the lowest in the northernmost state Schleswig-Holstein with 6.05% (6.07%). Prevalence was higher in men with 8.84% (8.68%) than in women with 7.98% (7.71%). In 2022, the standardized total prevalence amounts to 9.34% in Germany. CONCLUSIONS: This method to estimate diabetes prevalence by means of prescription data presents valid results compared to other epidemiological studies. A simple, fast and re-usable algorithm allows calculating nationwide prevalence estimates on a regional level by secondary use of large data sources. Quick analyses and demographic forecasts can support care providers and payors to plan health care and expenses more efficiently to match current and future regional demand.