Diastolic dysfunction of the heart has a significant importance, especially in patients presenting with dyspnea or clinical syndrome of heart failure. Assessment of diastolic functions is now an integral part of all echo studies. Assessment should be done in all vulnerable patients for heart failure and those presenting with unexplained dyspnea. This chapter will discuss the practical modern approach for assessing diastolic functions along with their limitations. Basic study starts with measurements in mitral Doppler (includes velocity of E wave, A wave, E/A ratio, DT, A-wave duration), valsalva studies and two-dimensional (2D) echo. Echocardiography combined with Doppler and tissue Doppler imaging is the most practical method used for the evaluation of diastolic dysfunction of the heart.