Regression of cardiovascular structural changes is a main goal of antihypertensive treatment. Nitrendipine is a calcium antagonist of the dihydropiridine group that may be given once daily. In different animal models of experimental hypertension, nitrendipine was shown to reduce blood pressure (BP) and left ventricular (LV) mass, to prevent early mortality, and to limit the development of vascular lesions. It has also been proposed that nitrendipine is able to preserve tissue integrity and increase life span in malignant hypertension, because it prevents a deleterious calcium overload in the heart and arterial vessels. In humans, the effect of nitrendipine on LV mass has been evaluated in a limited number of studies with conflicting results. It has been shown that nitrendipine is able to increase the compliance of large arteries: its effect on vascular structural changes has never been reported. In this study, nitrendipine (20 mg o.d.) was given to 10 hypertensive patients. BP, (ambulatory BP monitoring) heart rate (HR), LV mass and function (TM echo, 2D guided), forearm minimal vascular resistance (min VR = BP/max blood flow—venous occlusion plethysmography—taken as an index of vascular STC), plasma renin activity (PRA), plasma catecholamines (NE and E), and aldosterone (ALD) were measured during placebo, after 2 and 6 months of treatment. BP was significantly reduced and HR was slightly increased. After 6 months of treatment a significant reduction of LV mass index (p < 0.001) and of min VR (p < 0.002) was observed. Before and during treatment LV systolic function. both at rest and during stress (handgrip and cold pressor tests), evaluated by fractional shortening as related to end-systolic stress, was in every case within 95% confidence limits calculated in normal subjects. PRA and ALD did not change, and plasma NE was slightly increased (p < 0.05). These results indicate that a significant regression of STC in the heart and in the small resistance vessels may he observed after long-term treatment with nitrendipine in essential hypertensive patients.