Radionuclide angiography (RNA), performed by the equilibrium technique, is a non invasive method for the evaluation of ventricular function. RNA is performed after labelling the blood pool with a small amount of radioactivity. Image acquisition is gated to the patient's electrocardiogram. Serial images of the cardiac area are recorded over several cardiac cycles. After processing, it is possible not only to assess the cardiac activity visually but also to obtain quantitative parameters of cardiac function. Ventricular ejection fraction can be easily calculated from the time activity curve. Besides global ejection fraction, other parameters can be obtained, such as regional ejection fraction, peak filling and peak emptying rates and time to peak filling and peak emptying. Valuable additional information can be obtained from these and other parameters, for the diagnosis, evaluation of extension and prognosis of Coronary Artery Disease. Valvular Heart Disease and Cardiomyopathies are other areas in which RNA at rest or during exercise (or pharmacological interventions) has given an important contribution.