A health survey of middle-aged men was carried out in 1970-73 in the municipality of Uppsala. Subjects with hypertension, hyperlipidaemia, reduced glucose tolerance, and smokers were invited to join various therapy groups. By 1980 this multifactorial intervention programme had thus been running for 10 years. This report describes the results of a follow-up undertaken to evaluate the efficacy of the programme. The annual rate of fatal myocardial infarction (MI) was lower among the participants (n = 2322) in the health examination as well as among participants and non-participants (n = 446) combined than among the male Swedish population of the same age (162 and 187 compared with 296 per 100 000 men, respectively). The annual rate of non-fatal MI among participants and non-participants combined was 295 per 100 000 men, which is lower than in other Swedish cities. In the hypertensive group (n = 126), six men had fatal and seven non-fatal MI. These 13 men had higher blood pressures (BPs) from the start than the other hypertensives. In addition, their BP reduction was smaller than in a control group randomly selected among the hypertensive subjects. In the hyperlipidaemic treatment group (n = 363) there were eight fatal and 10 non-fatal MIs. Nine of these events occurred in individuals who had dropped out from therapy. It is suggested that the low total mortality and the low rates of fatal and non-fatal MI in this middle-aged male population may be related to the multifactorial intervention programme, as the incidences were also low among the treated high-risk groups.