Objectives: We analysed predictors of 1-year mortality following acute myocardial infarction in patients with diabetes mellitus by applying uni- and multivariate statistics on the DIGAMI cohort. Background: Diabetic patients with acute myocardial infarction have a poor prognosis. This may depend on a poor metabolic control, a hypothesis that was tested in DIGAMI, a prospective randomised study. In this trial institution of immediate intensive insulin treatment reduced 1-year mortality by 30%. Methods: We recruited 620 diabetic patients with acute myocardial infarction, 314 of whom served as controls, while the remaining 306 patients were treated with an acute insulin–glucose infusion followed by multidose subcutaneous insulin. Results: Age, previous myocardial damage, duration of the diabetes and previous insulin therapy were significantly related to 1-year mortality, while conventional risk factors lacked independent prognostic weight. Female sex was not linked to mortality when controlling for the confounding effects of other predictors. One of the strongest predictors of a fatal outcome, in particular during the hospital phase, was blood glucose at hospital admission. Beta-blockade appeared to exert a striking, independent secondary-preventive effect. Conclusions: It seems that good metabolic control and not conventional risk factors is of major importance for diabetic patients sustaining acute myocardial infarction. Also treatment with beta-blockade seems to be of special importance in this category of patients.