Objectives To test our hypothesis that obese adolescents have left ventricular (LV) dysfunction and remodeling that are associated with markers of cardiovascular risk and insulin resistance (IR). Study design In a cross-sectional study of 44 obese and 14 lean age-, sex-, Tanner stage-, and race-matched adolescents, IR, markers of cardiovascular risks, conventional and 2-dimensional speckle tracking echocardiography measures of LV function and structure were evaluated and compared. Results The obese adolescents had significantly increased body mass index Z-score, systolic blood pressure, fasting insulin, IR, and atherogenic lipids compared with the lean adolescents. A subgroup of obese adolescents had LV remodeling characterized by significantly increased LV mass index (g/m2.7) and relative wall thickness. Almost all obese adolescents had LV dysfunction with peak LV global longitudinal strain (GLS, %), systolic GLS rate (GLSR, %/s), and early diastolic GLSR significantly lower than in lean adolescents and in the normal pediatric population. Body mass index Z-score predicted LV remodeling (LV mass index [R2 = 0.34] and relative wall thickness [R2 0.10]), and peak LV GLS (R2 0.15), and along with systolic blood pressure, predicted systolic GLSR (R2 0.16); (P <.01 for all). Fasting insulin predicted early diastolic GLSR (R;bsupesup 0.17, P <.01). Conclusions Obese adolescents have subclinical ventricular dysfunction associated with the severity of obesity, increased systolic blood pressure, and IR. Ventricular remodeling is present in a subgroup of obese adolescents in association with the severity of obesity. These findings suggest that obesity may have an early impact on the cardiovascular health of obese adolescents.