Arterial wall stiffness is an important independent risk factor for cardiovascular disease in hypertensive patients, which is further exacerbated by co-existent diabetes mellitus. Increased arterial stiffness is directly associated with an increase in pulse wave velocity (PWV) and indirectly with increased central and peripheral blood pressure. Following a two-week placebo run-in period, 27 patients with mild to moderate essential hypertension and Type 2 diabetes mellitus, were randomised to once daily treatment with either telmisartan 40 mg or placebo for three weeks, and after a two-week washout period, crossed-over to the alternative treatment for a further three weeks. Carotid/femoral and carotid/radial PWV were measured non-invasively using the automatic Complior(R) device, and central parameters (central blood pressure, pulse contour analysis, and augmentation index) were measured using the SphygmoCo(R) system, at the start and end of each treatment period. Compared with placebo, treatment with telmisartan significantly reduced carotid/femoral PWV (mean adjusted treatment difference -0.95 m/s, 95% confidence intervals: -1.67, -0.23 m/s, p=0.013), as well as peripheral and central diastolic, systolic and pulse pressure. In conclusion, the results of this study show that telmisartan is effective in reducing arterial stiffness in hypertensive patients with Type 2 diabetes mellitus, and may potentially have beneficial effects on cardiovascular outcomes, beyond blood-pressure lowering effects, in this patient group.