There is a wealth of solid evidence from animal and human studies for a large number of (modifiable) factors showing that unfavorable levels of these factors or their presence increase the risk of developing atherosclerosis early in life, i.e., in childhood, adolescence, and young adulthood. The consequences of these vascular abnormalities are an increased risk of suffering an atherosclerotic symptomatic vascular event earlier in life than anticipated. Prevention of unfavorable levels of risk factors and atherosclerosis from developing is key. Lifestyle Interventions during childhood and adolescence have lifelong effects on health outcomes. In fact, these time periods provide a unique window of opportunity for lifestyle change, as imprinted healthy behavior has aggregated positive cardiovascular and psychosocial health effects lasting years. Regular cardiovascular risk factor measurement, with or without noninvasive assessment of atherosclerosis, integrated into an individual lifetime cardiovascular risk estimation, may facilitate management of the growing group of young people with increased cardiovascular risk in society.