OBJECTIVE: Lifelong steroid therapy and exposure to adrenal androgen excess in 21-hydroxylase deficient (21-OHD) congenital adrenal hyperplasia (CAH) children and adolescents may modify circadian blood pressure profile and result in vascular complications. The objective of the study was to evaluate vascular abnormalities in 21-OHD children and adolescents in relation to their genotypes. DESIGN: A cross-sectional study conducted at a tertiary referral center. PATIENTS: Seventy patients with 21-OHD CAH (27 boys), aged from 3 to 17.9 years: 9 with nonclassic CAH, 61 with classic CAH: 10 with simple virilising (SV) and 51 with salt wasting CAH (13-Del/Del, 8-Del/I2G, 7-I2G/I2G and 23-other genotypes). MAIN OUTCOMES MEASURES: The assessment of systolic and diastolic BP (SBP, DBP) loads, night dip% and arterial ambulatory stiffness index (AASI) in 21-OHD CAH patients.