To determine the prevalence of unrecognized silent myocardial ischemia, 925 noninsulin-dependent diabetic outpatients (333 women and 592 men), aged 40 to 65 years, asymptomatic, free from known coronary artery disease (CAD), advanced diabetic retinopathy, and nephropathy, severe hypertension, and poor prognosis disease, underwent exercise electrocardiogram (ECG), followed, if abnormal, by an exercise thallium scintigraphy. The exercise ECG tests were abnormal in 112 patients (12.1%, 31 women, 81 men), of whom 59 (6.4%, 12 women, 47 men) had perfusion defects at thallium scintigraphy. Adopting the more restrictive criteria (positive response to both tests) the prevalence of silent CAD resulted in 6.4%. Multivariate analysis showed that in the whole population and in the men, the associated independent risk factors were age, total cholesterol, proteinuria, and ST-T abnormalities at ECG at rest. This last factor had the highest odds ratio (9.27, confidence interval [CI] 4.44 to 19.38) and was the only one identified also in women. The relevance of ST-T abnormalities at ECG at rest as a predicting factor for silent CAD outlines the importance of a periodical ECG at rest in noninsulin-dependent diabetic patients and suggests an indication of performance of further investigations in presence of these abnormalities.