Type A behavior pattern (TABP) is a behavioral constellation that includes hostility, aggressiveness, competitiveness, time urgency and impatience. These behaviors are elicited when a subject is confronted with a challenge situation. These subjects are coronary-risk population. Currently, the American Heart Association considers this behavior pattern a risk factor, the same as hypercholesterolemia or hypertension. TABP may be detected early in childhood. We applied five times a questionnaire to a 39 elementary school children sample. As the age increases, the scores increased. These studies are the onset of longitudinal research with Mexican population; the goal will be to establish the pathogenesis of coronary heart disease and ways of prevention.