To determine the prevalence of left ventricular diastolic dysfunction in asymptomatic, normotensive patients with type 2 diabetes mellitus, we studied 61 consecutive normotensive patients with type 2 diabetes using conventional Doppler echocardiography at rest (deceleration time, isovolumic relaxation time, early diastolic velocity [E]/peak atrial systolic velocity [A] ratio), and during the Valsalva maneuver. In addition, mitral annular velocity and velocity of flow propagation were assessed in all patients using tissue Doppler imaging (TDI) and color M-mode echocardiography. A standard resting echocardiogram excluded significant valvular disease and stress echocardiography excluded significant coronary artery disease in those with diastolic dysfunction. Diastolic dysfunction was found in 43 of 57 patients (75%) when all of the above echocardiographic techniques were used. TDI detected diastolic dysfunction more often (63%) than any other echocardiographic approach. Thus, the prevalence of left ventricular diastolic dysfunction in asymptomatic, normotensive patients with type 2 diabetes without significant coronary artery disease is much higher than previously suspected. TDI markedly improved the echocardiographic detection of diastolic dysfunction in asymptomatic patients with type 2 diabetes.