Background: The population-based MONICA Augsburg studies (age 25-74 years) were used to quantify the impact of diabetes mellitus (DM) on the risk of myocardial infarction (MI) and 28-day case fatality. Methods and results: During the 10-year MONICA study period a total of 12,766 persons took part in the CVD risk factor surveys; 551 (men 4.2%, women 3.6%) had DM. A parental history of DM was observed in 33% of the DM and 19% of the non-DM participants with a significantly increased risk profil. During 1985-1994 a total of 9,662 cases with fatal and non-fatal MI were registered; 2,775 (men 24.8%, women 38.2%) had DM. Men with DM showed a 3.7-fold (95% Confidence- Interval 3.5-3.9) and diabetic women showed a 5.9-fold (95% CI 5.5-6.4) increased risk of MI. The diabetic MI patients had a 50% (women) to 70% (men) increased 28-day case fatality (p < 0.001). Conclusions: Aggressive strategies of risk factor prevention should be implemented even in the prediabetic stage, especially in subjects with a positive parental history. Diagnostic guidelines and treatment strategies for DM patients with CHD should be issued by the diabetological and cardiological physicians' associations.