Diabetes presents a higher risk of both symptomatic and asymptomatic coronary artery disease (CAD). Myocardial perfusion SPECT, particularly associated with Gated acquisition, makes it possible to diagnose CAD on the basis of the presence and extent of perfusion defects, and to carry out the stratification of the cardiological risk (infarction or cardiac death) by analyzing the results of perfusion and of the functional data (ejection fraction, EF, and wall movement). Gated myocardial SPECT in the diagnosis and stratification of risk has proved superior to clinical evaluation or the exercise test alone, and it is also superior to echostress/dobutamine in the evaluation of monovasal disease. These data have been confirmed not only in the population at large but also in the diabetic population, making the technique important also in such patients also affected by coronary disease which is earlier and more advanced in diagnosis. Scintigraphic data make it possible to classify patients into various risk categories (low, intermediate and high) on the basis of which a specific therapeutic approach can be established. The present review develops the above concepts, taking into consideration the consolidated studies present in the literature, for the purpose of pinpointing the diagnostic approach in which exercise or SPECT myocardium-scintigraphy can be assigned.