Hypertension or raised blood pressure (BP) was previously rare in children and adolescents, but the prevalence is dramatically changing mainly due to the critical influence of childhood obesity. Ten years ago at the Hypertension Clinic at Groote Schuur Hospital referral of children and adolescents with hypertension was uncommon and usually associated with defined secondary causes, but in the past 10 years we have seen a dramatic increase in referrals.