The aim of this study was to determine which BP measurement is the best related to target organ damage. There were 49 young adults with a history of childhood hypertension (school check-up) and to increase the prevalence of hypertension in the study group, 25 males 24 females, aged 20.1 +/- 2.2 years old were included in the study. All patients had a diurnal ambulatory BP monitoring and office BP measurements taken with a sphygmomanometer and with an oscillometric device during a 15 minute period monitoring (Dinamap BP). Echocardiography and blood samples (cholesterol and triglycerides) were performed in all patients. In contrast with office BP, a mean ambulatory SBP and mean Dinamap SBP significantly correlated to left ventricular mass index (LVMI) (P < 0.01). There was also a correlation between triglycerides and mean Dinamap SBP (P < 0.01) which could suggest an early insulin resistance. In this selected population, a short period BP monitoring, as well as ambulatory BP, is more closely related to LVMI than office BP.