Lack of social support has been found to predict all causes of mortality in population studies. It has often been assumed that the lack of social ties is associated with the general social conditions related to mortality and has little to do with specific disease etiology. So far, the association between lack of support and cardiovascular disease incidence has not been demonstrated. We have measured both emotional support from very close persons ("attachment") and the support provided by the extended network ("social integration"). This measure was applied along with standard measures of traditional risk factors to a random sample of 50-year-old men born in Gothenborg in 1933. All men (n = 736) were followed for 6 years and the incidence of myocardial infarction and death from coronary heart disease (CHD) was determined. Both "attachment" and "social integration" were lower in men who contracted CHD, with a significant effect for social integration (p = 0.04) and an almost significant effect for attachment (p = 0.07). When controlling for other risk factors in multiple logistic regression analyses, both factors remained as significant predictors of new CHD events. Smoking and lack of social support were the two leading risk factors for CHD in these middle-aged men.