In 1990, the three French MONICA centres recorded comparable frequencies of myocardial infarction admitted and not admitted to hospital. However, the mortality on the 28th day revealed an excess hospital mortality in Lille compared to Strasbourg and Toulouse (p < 0.001). Toulouse infarct patients were younger. The emergency management of coronary patients subsequently admitted to hospital also differed (16.7% patients in Lille vs 40% in Strasbourg and 24.3% in Toulouse) (p < 0.01). In Lille, 41.6% of patients had known coronary heart disease vs 30.4% in Toulouse and 38.4% in Strasbourg (p < 0.05). These three characteristics influenced the mortality. During admission, considerable differences were observed in the therapeutic strategies in the 3 centres: in Toulouse, angioplasty was predominant (51.4%) together with prescription of calcium channel blockers (65.5%) and aspirin (82.5%). In Lille, there were a high prescription (20.3%) of antiplatelets other than aspirin during the acute phase compared to Toulouse (0.6%) and Strasbourg (7.3%). In Strasbourg, the cardiologists of the department rarely used angioplasty during the acute phase, but were the leading prescribers of beta-blockers. Fibrinolysis was performed in 4 out of 10 patients in the three centres. Aspirin was used in more than 7 out of 10 patients during the acute phase in all MONICA centres, but at a variable dosage: doses greater than or equal to 250 mg per day were prescribed in Toulouse (97.6%) and Strasbourg 82.8%), while, in Lille, only one out of 2 patients received this dosage (50.6%).