The risk for adult cardiovascular disease (CVD) begins to develop in childhood and adolescence, but only recently has it been possible to evaluate the breadth of childhood cardiovascular risk factors and their relative contributions to adult CVD risk. This chapter highlights both well-established risk factors such as birth weight and childhood body mass index (BMI), as well as emerging evidence regarding in utero exposures, childhood lipids, blood pressure, and clustering of risk factors in childhood, as well as psychosocial factors such as adverse childhood experiences. Several of these risk factors have previously been associated with adult CV risk factors or preclinical atherosclerotic markers, but longitudinal assessment of the relationship between childhood risk factors and adult CV events has been sparse to this point. Here, we review the evidence for these relationships, as well as the relative impact of childhood versus adulthood measured risk factors, where such information is available. Discussion will focus on the implications of childhood risk factor assessment in identifying individuals at risk of adult CVD.