The prevalence of type-2 diabetes is increasing dramatically, primarily being driven by environmental factors, like dietary and exercise habits. In this study we investigated the association of physical activity and acute coronary events in diabetic patients, an issue that has not been adequately studied so far.Cross-sectional, case-control study.We studied demographic, lifestyle, dietary and clinical information in 216 hospitalized diabetic patients (171 men, 45 women) with a first event of an acute coronary syndrome and 196 frequency matched (by age and sex) diabetic controls (154 men, 42 women) without any evidence of coronary heart disease. Physical activity was evaluated according to the kcal/min expended and the weekly frequency of exercise. Physically active were considered those who reported non-occupational physical activity >once/week (at least 30 min/time).Seventy-eight (36%) of 216 patients and 110 (56%) of 196 controls were classified as physically active (P<0.001). Multivariate conditional logistic regression analysis revealed that the odds ratio for developing an acute coronary event in diabetic subjects who reported moderate levels of physical activity was 0.22 [95% confidence interval (CI): 0.12-0.47], while in those who reported vigorous physical activity it was 0.33 (95% CI: 0.21-0.59), after adjusting for age, sex, and the conventional cardiovascular risk factors.Physical activity (moderate and vigorous) seems to be associated with a lower prevalence of acute coronary events in the investigated group of diabetic subjects. Light physical activity does not seem to have any significant association with the development of acute coronary events.