The advent of gated myocardial SPECT has achieved one-stop imaging in coronary artery diseases. Perfusion at rest and stress is measured and quantified using software. Myocardial contractility can be determined by quantifying the global function or regional contractility markers such as wall motion or systolic thickening. Excellent reproducibility was shown for ejection fraction and left ventricular volumes and mass. Improvement of the ejection fraction by 5% or a decrease of volumes by 10 ml can be used as criteria on a post-operative or follow-up scan. To achieve post-operative global improvements, an increase of systolic thickening >15% of regional segments is needed. Even the prolonged transient stunning can be detected on gated myocardial SPECT as one gated SPECT indicates the perfusion and contractility of each segment. Low-dose dobutamine-challenged gated SPECT is feasible and is believed to parallel low-dose dobutamine echocardiography for determination of myocardial viability. Gated SPECT was also helpful to differentiate artifacts and for risk stratification of diabetic patients ; normal perfusion with abnormal function means a worse prognosis. Gated myocardial SPECT is mandatory if SPECT cameras have the capability of gating because it provides clinicians with information not only on diagnosis but also on prognosis, treatment strategy and risk stratification.