Abstract Objective To investigate the diagnostic and therapeutic strategies applied to patients currently treated for coronary artery disease (CAD) in relation to the presence of diabetes mellitus (DM). Background Despite the declining mortality related to CAD, patients with DM have not experienced similar benefits and still have a deleterious prognosis compared to their non-DM counterparts. Methods The Euro Heart Survey on Diabetes and the Heart was conducted between February 2003 and January 2004 in 110 centres across 25 countries. Consecutive patients were recruited while referred to a cardiologist due to CAD, when admitted to hospital wards or visiting outpatient clinics. DM was defined as a diagnosis established before enrolment. Results DM was reported in 1524 (31%) of 4961 patients enrolled. Among the 1872 patients with acute coronary syndrome (ACS), adjusting for differences in clinical characteristics at baseline, DM status did not influence the propensity to use different pharmacological agents (except renin-angiotensin-aldosterone system blockers) or coronary interventions. In patients with stable CAD (n = 2854) secondary prevention guidelines were poorly adhered to: 30% achieved blood pressure targets (< 140/90 mmHg), and lipid control was adequate in a minority of DM and non-DM patients (total cholesterol > 5 mmol/l: 55 versus 47%; low-density lipoprotein cholesterol > 3 mmol/l: 57 versus 51%). Conclusions Differences in the treatment and intervention patterns of patients with ACS disappear when corrected for the clinical confounders detected. Despite the recommendations and the high cardiovascular risk, an inadequate and less aggressive management was demonstrated in the contemporary patients with diabetes and stable CAD compared with the non-diabetic counterparts. Eur J Cardiovasc Prev Rehabil 14: 28-36 © 2007 The European Society of Cardiology