Hypertension is a key risk factor for developing cardiovascular and renal diseases and one of the most important causes of morbidity and mortality worldwide. Iterative measurement of the clinical blood pressure is the method proposed by international and national organizations to establish the diagnosis of hypertension. However, current data suggest that neither in-hospital nor self home blood pressure measurement is sensitive and specific enough for one to recommend them as the sole diagnostic test. More accurate diagnosis of hypertension would allow a significant cost saving by reducing both cardiovascular and renal complication burden, and costs induced by erroneously diagnosing normal subjects as hypertensives. Therefore, 24h ABPM is increasingly becoming the gold standard for diagnosing hypertension.