Purpose. This study aimed to determine the prognostic value of coronary angiography with multislice computed tomography (MSCT) in a population of diabetic subjects with known or suspected ischaemic heart disease compared with a nondiabetic control population. Materials and methods. Forty-nine patients with type 2 diabetes mellitus (DM) [group 1; mean age 67.7 +/- 8.8 years; 32 men; mean body mass index (BMI) 28 +/- 3.9] and 49 patients without DM (group 2, with similar demographic and clinical characteristics) were studied with MSCT coronary angiography to exclude the presence of ischaemic coronary artery disease (CAD). Each group comprised 26 patients (53%) with no history of ischaemic coronary disease and 23 patients (47%) with a history of myocardial infarction and/or myocardial revascularisation. Clinical follow-up was performed by analysing correlations between the rate of cumulative cardiac events (cardiac death, nonfatal myocardial infarction, unstable angina, and myocardial revascularisation), the severity of CAD identified on MSCT, and the presence of DM as a cardiovascular risk factor. Results. At mean follow-up of 20 months, univariate analysis of survival showed significant differences between the two groups (group 1 vs. group 2, p=0.046). Moreover, the cumulative cardiac event rate correlated significantly with the presence of significant CAD (>50% stenosis) in both groups (group 1: p=0.003; group 2: p=0.0004). Conclusions. Event-free survival is significantly lower in the diabetic population compared with the normal control population (p=0.046) and is closely correlated with the presence of significant CAD. MSCT is an effective method for stratifying such risk and, together with high diagnostic accuracy, provides additional prognostic value.