Abstract: PET myocardial perfusion imaging permits the measurement of regional myocardial blood flow (MBF) and coronary flow reserve (CFR) in absolute units. The short physical half-life of the flow radiotracers used for these measurements allows repeatedly operating PET myocardial perfusion imaging during the same study session and thus, assessment of MBF at baseline, during cold pressor testing and pharmacologic vasodilation, which contributes to a comprehensive assessment of the endothelium-dependent and endothelium-independent CFR function. Therefore, such measurements of MBF could serve as an important tool to detect early stages of the development of coronary artery disease, multi-vessel coronary artery disease and microvascular disease, indicate an impairment of endothelium-dependent coronary circulatory function, provide predictive information for future cardiovascular events, and contribute to the clinical treatment programs development and therapeutic efficiency testing. The primary technical aspects and clinical applications of PET myocardial perfusion imaging are introduced in this paper.