BACKGROUND: The strength of each heart beat and the stiffness of large arteries contribute to blood pressure (BP). When the large arteries are stiff and their resistance greater, the afterload increases and this may change the function of the heart. However, the relation between common carotid artery stiffness and heart function in hypertensive patients has not been clarified. METHODS: Two hundred and twenty hypertensive patients underwent transthoracic and carotid echocardiography. Measurements of local arterial stiffness were taken at the right common carotid artery level and stiffness parameter (beta), pressure-strain elasticity modulus and intima-media thickness were calculated. Brachial cuff BP was measured just before starting the carotid study. The patients with any cardiovascular disease, diabetes mellitus, stroke, transient ischemic attack, or carotid stenosis were excluded. RESULTS: Carotid artery stiffness parameter (beta) was correlated with age and left ventricular mass index (p < 0.005). Even though beta was not correlated with LV systolic function, it was inversely correlated with diastolic function as measured by early mitral annular velocity. When the artery was stiffer, early mitral annular velocity (e') decreased (p < 0.001) and the index of left atrial (LA) pressure (early diastolic mitral inflow E velocity/e') increased (p = 0.001). In logistic regression, diastolic dysfunction was affected by age (beta -0.385, p = 0.001), LA volume index (beta 0.175, p = 0.013) and beta (beta -0.273, p = 0.019). CONCLUSION: In hypertensive patients, changes in carotid artery stiffness can affect the diastolic function, independent of age and LA volume index. Therefore, measurements and control of carotid stiffness can play an important role in the prevention of diastolic heart failure.