Coronary artery disease is a common, serious and insidious complication of diabetes. Myocardial ischaemia is often silent. All diabetics do not have the same coronary risk and, therefore, it is important to determine which investigations to perform and which patients. This strategy is justified because it allows identification of these cases which require a medical or an invasive (angioplasty, surgical revascularisation) approach, as these interventions may improve the prognosis. The first stage is clinical (investigation of cardiovascular risk factors). When more than two risk factors are found, further investigations are justified. Exercise stress testing provide reassuring diagnostic and prognostic data when maximal and negative. When sub-maximal, impossible or significantly ischaemic, a second investigation is useful. Holter ECG recording with analysis of ST variation lacks sensitivity and, above all, specificity. The diagnostic value of perfusion myocardial scintigraphy in the diabetic is not as good as that observed in the general population, but its prognostic value remains good. Ischaemia involving over 20% of the myocardium justifies therapeutic investigation. Stress echocardiography has been validated in the diagnosis and prognosis of coronary artery disease and its sensitivity and specificity are probably the same as those of scintigraphy. The authors conclude that the asymptomatic diabetic requires clinical and staged paraclinical investigation to assess prognosis and, depending on the results, the adoption of a beneficial therapeutic strategy.