Background: This study was designed to determine the clinical risk for hard events after normal single-photon emission computed tomography (SPECT) and to identify the predictors of increased risk in asymptomatic patients with diabetes mellitus, based on a Japanese Assessment of Cardiac Events and Survival Studies by quantitative gated SPECT (J-ACCESS)-2 study. Methods and Results: A total of 513 consecutive asymptomatic patients who underwent stress ^99mTc-tetrofosmin SPECT in Japan were included in this study. Based on SPECT image and QGS data, 319 had a summed stress score ≤3, a summed difference score <2 and normal cardiac function (end-systolic volume ≤60 ml, males, ≤40 ml, females; left ventricular ejection fraction ≥49%, males, ≥50%, females). Myocardial perfusion was normal in 62% of this study population. During a 3-year follow-up, there were a total of 8 cardiac major events (2.5%): 2 cases of sudden death, 5 of acute coronary syndrome, and 1 of hospitalization because of congestive heart failure. The annual major event rate was 0.8%. Subjects undergoing coronary angiography had significantly more major events than those who did not among normal SPECT subjects (P=0.01). Kaplan-Meier analysis showed that the cardiac major events rate was very low, and subjects with normal SPECT can be considered as low risk among asymptomatic patients with diabetes. Conclusions: An excellent prognosis was associated with a normal SPECT in asymptomatic patients with diabetes, so these patients can be exempted from further invasive procedure.  (Circ J 2010; 74: 1916 - 1921)