Cross-sectional data often fail to show beneficial effects of antihypertensive therapy in patients with hypertension. We, therefore, examined the influence of hypertension control on left ventricular (LV) structure in diabetic persons separated into those having and not having any known cardiovascular disease (CVD) symptoms. The study population consisted of 394 subjects with type II diabetes. According to the presence of CVD, subjects were classified as symptomatic (N=181) or asymptomatic (N=213). In addition, three groups were differentiated: controlled hypertensives (CHs), that is, known hypertension with normal blood pressure (BP), uncontrolled hypertensives (UHs), that is, elevated BP regardless of antihypertensive medication, and normotensives (Ns). Symptomatic subjects showed a significantly higher prevalence of LV hypertrophy (LVH) (34.5 vs 23.4%, P<0.02). In contrast to symptomatic subjects where hypertension control status had no further significant impact on LV geometry, a considerable impact on preservation of normal LV geometry was observed in asymptomatic persons (LVH of 30, 15 and 18% in UH, CH and N, respectively, P<0.001). Control of hypertension in early diabetes seems especially to prevent the development of concentric hypertrophy (24 vs 11% in UH vs CH, P<0.04). In conclusion, in subjects with diabetes and CVD, the prevalence of LV structural abnormalities is very high. Although in this population-based study setting, in the latter group BP control does not seem to positively influence LV mass and function, hypertension control in still asymptomatic diabetic persons is beneficial and has a considerable impact on preservation of normal LV geometry.