Echocardiography plays a central role in the assessment of left ventricular (LV) diastolic function, which is often a challenging task for the clinician. Normal diastolic function allows for the left ventricle to sufficiently fill and to generate the necessary stroke volume without exceeding certain pressure limits during filling. Diastolic dysfunction primarily results from increased resistance to ventricular filling, leading to an upward and leftward shift of LV pressure volume relation, often during exercise or tachycardia. The physiological hallmarks of LV diastolic dysfunction are impaired relaxation, loss of restoring forces, reduced diastolic compliance, and elevated filling pressure. When LV and left atrial pressures start to increase, patients may develop dyspnea and/or pulmonary congestion. The assessment of diastolic function has become particularly relevant, as approximately half of patients with heart failure have normal or near normal ejection fraction, a condition in which diastolic dysfunction is thought to be a key pathophysiologic mediator. Diastolic function is multifaceted, and there is no one echocardiographic measure that fully captures diastolic dysfunction. In this chapter, we review the measures routinely employed in the clinical evaluation of diastolic function and recommended by professional society guidelines, including mitral inflow Doppler, tissue Doppler early relaxation velocities, E/. e? ratio, left atrial size, and pulmonary pressure. We also review approaches to integrating these measures into an assessment of diastolic dysfunction and/or grade of dysfunction. By using combination of different echocardiographic indexes, diastolic performance can be reasonably estimated in most patients.