Prevalence of coronary artery disease (CAD) is high in diabetic patients while diagnosis of early stage of CAD remains demanding. This study evaluates prognostic value of coronary computed tomography angiography (CCTA) for long-term outcome to predict cardiac events in oligosymptomatic diabetic patients. A cohort of 108 consecutive diabetic patients without angina pectoris or known CAD, undergoing CCTA was included. 1379 consecutive patients without diabetes were defined as a control group. Coronary artery calcium score (CACS), segment involvement score (SIS) and the segment stenosis score (SSS) were documented. The end point was a composite of cardiac events defined as all-cause death, nonfatal myocardial infarction, or unstable angina requiring hospitalization. Follow up period was 66.0 ± 14.2 month. 98% of initially enrolled patient were followed. During follow-up period 10 cardiac events within the diabetic cohort and 48 within the non-diabetic cohort were observed. Annual event rate in diabetic and non-diabetic patients was 1.74 and 0.64% respectively. In diabetic patients a multivariate analysis showed significant prognostic value over Framingham Score for SIS with a hazard ratio (HR) of 2.98 (95% CI 1.02, 8.72; p = 0.047) and SSS (HR 4.47, 95% CI 1.21, 16.49; p = 0.025), while CACS did not add prognostic value in this cohort. Annual event rate was 0% in diabetic patients with SIS = 0 and 3.9% in diabetic patients with SIS ≥ 8. CCTA allows for improved risk prediction for subsequent cardiac events in oligosymptomatic diabetic patients.