This study examined children of 64 families for associations between a) family conflict and cohesion and b) plasma lipids, lipoproteins, and aggressiveness. Ratings of conflict and cohesion were obtained from parents. Children rated themselves on aggressiveness, one component of Type A behavior. The presence of conflict in the family was positively related to an unfavorable lipid profile (total plasma cholesterol/high-density lipoprotein cholesterol) among boys, but not girls. Family conflict predicted increased levels of aggression in girls, and in boys whose family cohesion was low. These findings suggest that stress in the family may play an important role in the development of coronary risk.