In Germany, about 7-9% of the population between 18 and 79 years currently suffer from diabetes mellitus. In 2002 and 2004, nationwide structured treatment programs (disease management programs, DMPs) were set up for people with diabetes and covered by statutory health insurance. Within the DMPs, 4.4 million people with type 2 diabetes and 0.3 million people with type 1 diabetes were cared for in 2022, which after taking into consideration age and gender as well as the regional differences in diabetes prevalence, this corresponds to a rate of approximately 82%. In the DMP for type 2 diabetes, quality of care, defined by contractually agreed indicators, is rated as good or even very good, with respect to many aspects. However, in the DMP for type 1 diabetes, this is true only for a few areas. Furthermore, there is substantial variation in the extent of achieving quality goals between participating practices. Over time, increasing as well as decreasing trends can be seen regarding different quality indicators. Positive findings are (1) very good metabolic control in patients in the DMP for type 2 diabetes; (2) continuous decrease in the occurrence of severe hypoglycemic events in the DMP for type 1 diabetes; and (3) very high rates of patient education in recent years.