We tested the hypothesis that renin–angiotensin system inhibition could reverse left ventricular diastolic dysfunction in patients with type 2 diabetes.Forty asymptomatic patients with type 2 diabetes were recruited in this double-blind cross-over trial. Left ventricular diastolic function was assessed at baseline with Doppler echocardiography; ratios of early to late peak flow velocity through the mitral orifice (E/A) and velocity time integral of early to late transmitral diastolic flow (VTIE/VTIA) were evaluated. In addition, plasma brain natriuretic peptide (BNP) was measured.Patients received randomly either ramipril (2.5mg/day), or telmisartan (40mg/day) or their combination for 3 months. Subsequently, every patient was crossed over to alternative regimens after a 2-week washout period. Measurements were repeated at the end of each treatment period.Both E/A and VTIE/VTIA ratios were increased (29 and 20% with ramipril, 25 and 23% with telmisartan and 36 and 28% with combination treatment, respectively, p<0.001), whereas plasma BNP levels were significantly reduced with all 3 regimens (9% with ramipril, 25% with telmisartan and 36% with combination, p<0.001).Both ramipril and telmisartan improve echocardiographic left ventricular diastolic indices and reduce plasma BNP levels in diabetic patients; their combination yields an even better therapeutic effect.