Several population-based surveys (MONICA, KORA) have been carried out in the Augsburg region since 1980. In the KORA Survey S4 (1999–2001) diabetes prevalence was examined for the first time by oral glucose tolerance tests (OGTT). In this study a prevalence of undiagnosed diabetes of 8.2% (age group 55–74 years) was found, which was almost as high as the frequency of known diabetes. In KORA F4, a follow-up investigation of all S4 participants, the prevalence of undiagnosed diabetes (2.2%) was also as high as diagnosed diabetes (2.4%) in the age group 35–59 years. In addition, 11% had prediabetes. In the KORA S4/F4 cohort study, the incidence of type 2 diabetes (age group 55–74 years) was assessed. Overall, 10.5% of the participants developed type 2 diabetes within 7 years, whereby men were twice as likely to develop diabetes as women. The standardised incidence rate (55–74 years) was 15.5 per 1000 person years (PY) (men: 20.2 per 1000 PY; women: 11.3 per 1000 PY). These figures correspond to approximately 270,000 new cases of diabetes per year in the older population in Germany. The data from the Augsburg region emphasise the fact that type 2 diabetes is a central challenge for the German health care system.