Patients with diabetes are at high risk for the development of coronary artery disease and have a significantly impaired prognosis after ST-elevation myocardial infarction (STEMI) as compared with non-diabetic patients. The beneficial effect of pharmaceutical treatment for secondary prevention after STEMI is proven also for diabetics, but little is known about its use in clinical practice. Between June 1994 and December 2000, consecutive patients with STEMI, admitted to hospital within 24 h of symptoms onset, were enrolled into the multicenter MITRA registry in 61 hospitals in Germany. We examined whether there were differences in the frequencies of pharmaceutical secondary prevention after STEMI and in long-term outcomes between diabetics and nondiabetics in 8206 patients who had been discharged alive and followed for a mean period of 17 months. The prevalence of diabetes in 8206 patients discharged alive after acute STEMI was 18%. Diabetics were older and more often female, and more often already had prior myocardial infarction (MI) and stroke than non-diabetics. As chronic discharge medication, diabetics received aspirin and betablockers less often, but more often ACE inhibitors than non-diabetics. The mortality rate 17 months after STEMI was nearly twice as high in diabetics than in non-diabetics (19.1% vs. 10.4%, p<0.01 at univariate analysis; OR=1.50 and 95% CI 1.27-1.77 at multivariate analysis). The combined endpoint of death, MI and stroke occurred in 25.8% of diabetics, but only in 15.8% of non-diabetics ( p<0.01). Long-term treatment with aspirin, betablockers and ACE inhibitors in diabetics was associated with a significant reduction of mortality. Diabetics received intensive pharmaceutical therapy for secondary prevention significantly less often than non-diabetics, although the beneficial effects of this treatment were similar or even more pronounced as compared with non-diabetics. Diabetes was an independent predictor of increased mortality in follow-up after acute STEMI. Intensifying secondary prevention by a more frequent use of established pharmaceutical regimes might improve the prognosis of diabetics after STEMI and prevent cardiovascular and cerebrovascular events.