As part of the ECTIM Study, the medical treatment given to male patients (25-64 years) 3 to 9 months after myocardial infarction (MI) were analysed in France and Northern Ireland. On univariate analysis, hypolipidaemic drugs, angiotensin-converting enzyme inhibitors and antiarrhythmic drugs were found to be prescribed more frequently in France, while beta-blockers were more common in Northern Ireland. No differences were found for diuretics, calcium channel blockers, antithrombotic and anti-anginal drugs, although the Northern Irish patients were mainly on antiplatelet drugs and nitrates, while the French patients received nitrates and non-nitrates, as well as oral anticoagulants and antiplatelet drugs in similar amounts. These differences remained after adjustment for personal history of diabetes, hyperlipidaemia, hypertension, and previous myocardial infarction, but the beta-blocker prescription was no longer significant. When the French centres were analysed, patients from Strasbourg were more frequently on oral anticoagulants and diuretics and less frequently on antiplatelet drugs, while patients from Toulouse had fewer anti-anginal drugs. Hence, although the current guidelines for secondary prevention of myocardial infarction are generally well applied in France and Northern Ireland, significant differences exist regarding the choice of the active drug.