The aim of this study, based on the data of the MONICA register in the Haute-Garonne, was to compare the prognosis and treatment of myocardial infarction between 1986 (253 cases) and 1989 (248 cases). The clinical features of these infarcts were comparable except for the previous history of ischaemic heart disease which was less common in 1989 (34.7% in 1986, 25.9% in 1989; p < 0.05). The 28th day mortality decreased from 8.4% in 1986 to 3.6% in 1989 without attaining statistical significance. The pre-hospital management was the same during the two periods of the study, with 67.6% of patients admitted to hospital before the 6th hour. Hospital care in 1986 and 1989 consisted of 5 days in the intensive care unit and lasted 14 days. Treatment changed considerably from 1986 to 1989. There was a higher incidence of platelet antiaggregant prescriptions (47.4% in 1986 and 80% in 1989; p < 0.001), of betablocker prescriptions (30.8% in 1986 and 47% in 1989; p < 0.05) and fibrinolytics (27.8% in 1986 and 52% in 1989; p < 0.01). Invasive procedures such as coronary angiography (83.5% in 1986 and 94% in 1989; p < 0.05), coronary angioplasty (20.3% in 1986 and 53.5% in 1989; p < 0.01) were undertaken in the majority of cases. The MONICA-Toulouse project shows a reduction in mortality and an increase in the use of therapeutic methods known to be effective in the reduction of mortality in myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)