This chapter tells how to assess diastolic function. Diastolic assessment by echo Doppler can be readily achieved in by using a comprehensive diastolic assessment—incorporating many 2D imaging, conventional, and tissue Doppler variables—as opposed to relying on any single, diastolic parameter, which can lead to errors. Comprehensive echocardiography with 2D imaging, and spectral and color Doppler—as well as newer techniques like speckle strain echocardiography—provide a complete assessment of cardiac diastolic function. This assessment, which includes LV mass and regional wall motion assessment, LA volume, transmitral, pulmonary venous, and tissue Doppler as well as estimation of PA systolic and diastolic pressures, can provide accurate assessments of diastolic function in the majority of patients. It is important to note that, as recommended in current guidelines, use of any single echo Doppler diastolic variable (e.g. only E/e’) in isolation, can lead to errors. Therefore, it is of utmost importance that a comprehensive assessment of LV diastolic function include integration of all available 2D and Doppler, and tissue Doppler variables to arrive at the most accurate diastolic assessment. 12 self-explanatory and comprehensive images are included in this chapter. 36 references are given at the end of the chapter to facilitate further reading.