IMPORTANCE There is increasing evidence supporting the importance of psychosocial factors in the pathophysiology of atherosclerotic disease. They have been shown to be associated with the population attributable risk formyocardial infarction. OBJECTIVE To determine if a score of favorable childhood psychosocial factors would be associated with decreased coronary artery calcification in adulthood. DESIGN, SETTING, AND PARTICIPANTS The analyseswere performed in 2015 using data gathered in 1980 and 2008 within the longitudinal Cardiovascular Risk in Young Finns Study. The data source consisted of 311 individuals who had psychosocial factors measured at ages 12 years to 18 years and coronary artery calcification measured 28 years later in adulthood. The summary measure of psychosocial factors in childhood comprised measures of socioeconomic factors, emotional factors, parental health behaviors, stressful events, self-regulation of the child, and social adjustment of the child. MAIN OUTCOMES AND MEASURES Coronary artery calcification at ages 40 years to 46 years. RESULTS Of the 311 participants, 48.2%were men. Of the participants, 55 (17.7%) had some calcium observed in their coronary arteries. A 1-SD increase in a favorable summary score of childhood psychological factors was associated with an adulthood coronary artery calcification probability of 0.85 (95%CI, 0.76-0.95) (P = .006). This inverse relationship remained significant after adjustment for age, sex, and conventional childhood risk factors (0.85; 95%CI, 0.74-0.97; P = .02) or for age, sex, adulthood conventional cardiovascular risk factors, socioeconomic status, social support, and depressive symptoms (0.83; 95%CI, 0.71-0.97; P = .02). CONCLUSIONS AND RELEVANCE In this longitudinal study, we observed an independent association between childhood psychosocial well-being and reduced coronary artery calcification in adulthood. A positive childhood psychosocial environment may decrease cardiovascular risk in adulthood and may represent a potentially modifiable risk determinant.