Diabetes mellitus is associated with a poor cardiovascular prognosis. Stress myocardial single-photon emission computed tomography (SPECT) reliably detects coronary ischaemia in asymptomatic patients. Our study aimed to evaluate the association between systolic and diastolic left ventricular function, left ventricular hypertrophy, endothelial function and the results of stress myocardial SPECT in 126 patients with type 2 diabetic patients with no cardiovascular symptoms. Thirty-three patients (26%) had abnormal SPECT results, 33 patients (26%) had intermediate (equivocal) results, and 60 patients (48%) had normal results. We found a significant association between an abnormal SPECT result, left ventricular diastolic dysfunction and impaired post-ischaemic dilatation of the brachial artery. No association was found between the SPECT result and systolic function and left ventricular hypertrophy, however. An abnormal SPECT result was significantly associated with left ventricular diastolic dysfunction and the deterioration of post-ischaemic dilatation of the brachial artery in asymptomatic patients with type 2 diabetes.