The major motivation for implementing myocardial Arterial Spin Labeling (ASL) is its repeatability, ease of use, and absence of exogenous contrast agents for cardiac perfusion MRI examinations. Research has been pursued in parallel in rodents and humans. Despite encouraging results in humans, myocardial ASL has not yet reached a wide range of applications likely due to a lack of broader validation and reproducibility studies. In rodents, however, myocardial ASL has been used in a variety of preclinical studies, contributing to a better understanding of cardiac disease mechanisms and physiology. This chapter introduces potential benefits, challenges, and existing acquisition and postprocessing methods. Clinical and preclinical applications are reviewed side by side, and recommendations are given for setting up protocols.