Reduction of arterial compliance leads to a higher systolic (SBP) and a lower diastolic blood pressure (DBP). The increasing occurrence of reduced arterial compliance is responsible for the steep increase in SBP after the age of 50 years and also for the constancy and later decline in DBP. Reduced arterial compliance will blur the relationship between mean arterial pressure and DBP. This may change the relationships between cardiovascular events and DBP. The possibility of non-causal co-existence of reduced compliance and atherosclerosis is discussed. Such a co-existence would markedly influence the relationship between cardiovascular events and DBP. Finally, the influence that reduced compliance might have on the shape of the relation between cardiovascular episodes and diastolic and systolic blood pressure is discussed.