Arterial blood pressure (BP) is widely believed to be a main risk factor for cardiovascular diseases. The chance to develop some kind of vascular injury is almost exponentially and continuously related to BP values at a given age. In accordance, the WHO stated the upper limits for diastolic and systolic BP beyond which it is reasonable to anticipate a clear statistic advantage from the hypotensive treatment (of either pharmacologic or other kind). However many studies have shown that the relation coefficient between BP values and the occurrence of cardiovascular diseases is on the whole quite weak, even under rigorously controlled conditions. This could be, at least in part, due to the fact that the severity of the cardiovascular damage depends on the "global" hypertensive load continuously charging the patient's cardiovascular system along the whole life: the "random" measurement of the BP is indeed a poor statistical index of such load because of the wide variability of BP with time. Thus many sources of BP variability have been studied, in order to develop multiple-measurement methods of BP monitoring hopefully with more prognostic power. In this article we review the major problems inherent to the methodological development of the serial full-automatic sphygmomanometric ambulatory BP monitoring, such as its concordance with different more traditional techniques, the statistic effectiveness of intermittent (versus continuous) sampling, the psychological impact of multiple cuff inflations during the day and the night.(ABSTRACT TRUNCATED AT 250 WORDS)