Determination of the actual blood pressure level increases with the number of blood pressure measurements. This explains why both ABPM and blood pressure self-measurement are superior to causal blood pressure determinations and why they show a higher correlation to a well-defined, hypertension-induced end organ damage (left ventricular hypertrophy). However, a disadvantage is that, up to now, the normal ranges were either insufficiently defined (ABPM) or not defined (SM). Although only limited experience exists in comparing ABPM with SM, it is suggested that both methods are valuable in the diagnosis and treatment of hypertension.