The diagnosis of left ventricular (LV) hypertrophy, an independent predictor of death and cardiovascular events, is difficult without using echocardiography. This study tested the hypothesis whether C-reactive protein (CRP) and B-type natriuretic peptide (BNP) would be useful to exclude echocardiographic LV hypertrophy. Consecutive hypertensive outpatients were asked to participate. Exclusion criteria were overt heart failure, severe renal insufficiency or any other severe concomitant illness. A venous blood sample was taken to measure plasma CRP and BNP concentrations. Echocardiographic LV hypertrophy was defined as LV mass ≥125 g/m² for men and ≥110 g/m² for women. In total, 320 patients were studied, and 37 patients (12%) had echocardiographic LV hypertrophy. Patients with LV hypertrophy were significantly older and had higher CRP and BNP concentrations and higher systolic blood pressure than those without LV hypertrophy. The optimal cut-off points for the diagnosis of LV hypertrophy were 35 pg/ml for BNP (sensitivity 73%, specificity 72%) and 2.5 mg/L for CRP (sensitivity 68%, specificity 59%). Only 1 of 123 patients with values of BNP and CRP less than the optimal cut-off point had echocardiographic LV hypertrophy, resulting in a high negative predictive value of 99% for the 2 blood tests combined to exclude LV hypertrophy. In conclusion, in hypertensive patients, echocardiographic LV hypertrophy can be excluded on the basis of a single blood sample for the determination of BNP and CRP.