Ambulatory hypertension (HT) and masked hypertension (MH, normal in clinic, high on ambulatory BP monitoring, ABPM) are associated with target organ damage (TOD) in adults, while white coat hypertension (WC, high in clinic, normal on monitor) is felt to be benign. We sought to determine if BP phenotype is associated with TOD in youth. We measured casual BP, ABPM, adiposity, LV mass index (LVMI), systolic and diastolic function (E/e’ ratio) and pulse wave velocity (PWV) in 365 adolescents (15.6 + 1.7 years, 63% white, 58% male). BP phenotype was determined by mean of 6 casual aneroid SBPs, and 24-hour SBP on ABPM (Spacelabs Inc., Snoqualmie, WA) by age, sex and height specific pediatric cut-points (normotensive, NT=224; WC=90; MH=23; HT=28). ANOVA was used to evaluate differences in CV risk factors and TOD across ABP phenotypes. General linear models were used to determine if BP phenotype was an independent predictor of TOD after adjusting for age, demographics, and adiposity. There were no differences in age, race/ethnicity. MH had more females, HT were heavier than NT. There was no difference in dipping but 24-hour SBP load (%readings above 95 th %ile) increased across groups (NT=12, WC=18, MH=55, HT=64, p≤0.02). There was no difference in LVM index (NT=31.8, WC=33.5, MH=32.6, HT=33.1 g/m 2.7 ). WC had reduced strain compared to MH (-19.5 vs -23%). There were significant differences in diastolic function, and arterial stiffness. BP phenotype remained a significant determinant of E/e’ and PWV after adjustment for age, sex and BMI z-score (p≤0.0006). We conclude that 24-hour BP phenotype adds to prediction of diastolic dysfunction and arterial stiffness but not LVMI or systolic function.