Adults with a left-ventricular mass index (LVMI) in grams normalized to height in meters^2.7 (LVMI g/m^2.7) >51 g/m^2.7 are more prone to cardiovascular and cerebrovascular events. We delineated the odds for cardiac structural sequelae amongst apparently normal white and African-American (AA) children with varying body mass indices (BMI) and office blood pressures. A total of 2,071 children with normal echocardiograms were categorized into risk groups based on BMI and systolic blood pressures (SBPs). Predictors of cardiac sequelae examined were age, sex, race, and z-scores (z) for BMI, SBP, and diastolic blood pressure. Cardiac sequelae measures included (LVMI g/m^2.7) >51 g/m^2.7, (LVMI) (g/m^2.7) z, left atrial size (LA^ht) (mm) z, and relative wall thickness z. Mean age was 14 ± 2 years with 56 % being male and 13 % being AA. Children were divided into “controls” (n = 1,059) and risk groups based on BMI and SBP. Odds ratio for LVMI (g/m^2.7) > 51.0 g/m^2.7, varied from 5.3 up to 8.5 in children with increased BMI. Both increased BMI and SBP z were associated with increased LVMI (g/m^2.7) z; however, BMI z had a stronger association. Increased BMI z and AA race were associated with greater LA^ht (mm) z. AA controls had a nonsignificantly increased LVMI z and a significantly increased LA^ht (mm) and RWT z. Being overweight or obese is associated with cardiac sequelae in children to the extent known to be associated with adverse outcomes in adults. Healthy AA children have unique cardiac structural differences.