Hypertension (HTN) is a significant global health issue. It is the major risk factor for atherosclerosis, leading to the development of cardiovascular disease (CVD). There is increasing evidence that HTN has its antecedents during childhood and that atherosclerosis is already present in adolescents. Thus early detection and intervention are crucial. HTN is also a risk factor for the progression to end-stage renal disease, a topic extremely relevant to pediatric nephrologists. While children are more likely to have secondary HTN, the prevalence of primary HTN appears to be increasing due to an epidemic of obesity. To identify children with HTN, clinicians should know normative values of blood pressure (BP) as well as the definition of HTN. Prevalence of HTN, factors influencing BP, and sequelae of childhood HTN are also reviewed in this chapter.