Antihypertensive drug treatment has been shown to significantly decrease cardiovascular morbidity and mortality rates in hypertensive subjects and to reduce the occurrence of major hypertension-related complications, such as stroke, coronary artery disease, congestive heart failure and renal insufficiency. Despite these favorable effects, several issues related to antihypertensive treatment remain to be clarified. This paper will discuss some of these issues, with particular reference to the effects of blood pressure lowering on renal diseases and coronary heart disease. It will also discuss the ongoing clinical trials aimed at clarifying some unsolved issues of antihypertensive treatment. The objective of the International Nifedipine GITS Study Intervention as a Goal in Hypertensive Treatment was to provide information on the effects of calcium antagonist treatment on high blood pressure values and on hypertension-related cardiovascular complications in a high-risk hypertensive population.