Microalbuminuria (MA) and C-reactive protein (CRP) levels are predictors of increased risk for left ventricular hypertrophy (LVH). Whether the strength of association between CRP and LVH is comparable to that of MA in hypertensive children is unknown. CRP and MA were measured in 64 children and adolescents with essential hypertension (HTN). In the entire population, CRP and MA showed positive relations with body mass index (BMI) (r = 0.30, p = 0.04 and r = 0.32, p = 0.04, respectively), systolic blood pressure (SBP) (r = 0.63, p = 0.03 and r = 0.58, p = 0.03, respectively), and LVH (r = 0.86, p < 0.001 and r = 0.81, p < 0.001, respectively). Patients with LVH (n = 23) had significantly higher BMI (p = 0.32), increased SBP (p = 0.031), and higher levels of CRP (p < 0.001) and MA (p < 0.001) compared with those without LVH. Multiple linear regression analysis demonstrated that CRP (r = 2.11, p < 0.001), MA (r = 1.94, p < 0.003), BMI (r = 0.53, p = 0.02), and SBP (r = 0.48, p = 0.04) were significantly associated with LVH. By analysis of covariance, CRP and MA were significantly different between patients who had LVH and those without LVH after adjustment for age, gender, BMI, SBP, SBP index, and diastolic blood pressure (p < 0.001 for the two markers). In conclusion, the strength of association between LVH and CRP is comparable to that of MA in children and adolescents with essential HTN.