A series of 299 men, aged 27-67, who had survived their first myocardial infarction (MI), have been compared with representative population samples with respect to tobacco consumption, alcoholic intemperance, physical activity during work and leisure time, occurrence of hypertension, and cholesterol and triglyceride levels in serum. The infarction patients comprised 90% of all surviving, diagnosed cases of primary MI in men aged 67 years or below during 1968-70 in Göteborg, Sweden. The comparison between infarction patients and general population samples revealed that the patients smoked more, and were less physically active during leisure time but not during work. They had more often a positive history of hypertension and treatment for high BP and their serum cholesterol and serum triglyceride values were higher. For all these variables the difference decreased with increasing age and was generally not statistically significant above the age of 60 years. Alcoholic intemperance was more common among infarction patients who died outside hospital, but there was no difference in this respect between surviving patients and the general population.