Diastolic function is essential for efficient systolic performance. A normal diastole allows left ventricle (LV) filling to occur under normal intracavitary pressure. It is an energy dependent process, as such affected by ischemia. Several factors influence diastolic function of the LV: the mitral valve area, the gradient between atrium and ventricle, LV relaxation and compliance, atrial compliance, the presence of sinus rhythm, the end-systolic volume. Echocardiography is the principal diagnostic tool to assess LV diastolic function noninvasively in clinical practice. Doppler evaluation allows to analyse each phase of LV diastole through measurement of transmitral and pulmonary veins flows velocities. Tissue Doppler echocardiography and color M-mode Doppler have also been introduced in the study of diastole. The use of echocardiography in the setting of diastolic dysfunction in ICU and operatory room has relevant implications in the management of haemodynamic instability, in vasoactive d rugs titration, in the detection of myocardial ischemia, and in performing prognostic stratification. These information can guide the management of cardiac patients undergoing cardiac and non cardiac surgery, in the perioperative phase, as well as in the management of critical ICU patients. On this basis evaluating the LV filling properties can contribute to improve the quality of treatments in such challenging situations.