The MONICA project is an international study coordinated by the WHO, designed to explain the important variations of coronary mortality observed in the industrialised countries over the last 20 years. Thirty-nine centres in 27 countries are participating in the project which, over a 10 year period will, in geographically determined zones; a) record the numbers of acute myocardial infarcts and coronary deaths, b) analyse the treatment of acute cardiac events, and c) evaluate the cardiovascular risk factors and preventive measures in the general population. The MONICA-France project comprises three registers (Bas-Rhin, Haute-Garonne and the urban community of Lille), and a coordinating centre. The preliminary results confirm the wide geographic variability of coronary mortality with a prevalence slightly higher in Alsace and the North than in the South-West of France. The approximative frequency of coronary events in France is estimated at 112,000 infarcts and over 175,000 acute coronary episodes and deaths. Information is provided about the severity of the principal coronary risk factors and the conditions of their treatment in the register zones. A study of the accessibility of emergency treatment of acute infarction in the Bas-Rhin area, has demonstrated the key role of the general practitioner as the first contact but confirmed the long delay to hospital admission which nullified the potential benefits of thrombolysis in a high proportion of cases. However, the significant decrease in hospital mortality of acute infarction observed over a 3 year period in the three register zones, is probably related to the number of patients thrombolysed in that time.