Over the last 15 years diastolic dysfunction has been recognized as a separate pathophysiological and clinical entity. At the same time two-dimensional echocardiography and Doppler echocardiography have evolved to become the method of choice to evaluate diastolic function in daily clinical practice. For correct interpretation and assessment of diastolic function parameters from Doppler velocity profiles, their relationship to the underlying pathophysiological mechanisms should be understood. This chapter will focus on the complex interaction between the different determinants of left ventricular diastolic function and the intracardiac Doppler velocity profiles. Ambiguities in interpretation and limitations of the technique as well as the latest technological advances and future directions will be discussed.