Abstract Background Ischemic Heart Disease (IHD) is the first ranked among most common causes of death involving cardiovascular and other diseases. The information on the prevalence of IHD in Thailand is lacking especially among patients with diabetes mellitus. The objectives of this study were to determine the prevalence of IHD among patients with diabetes mellitus and to determine factors associated with IHD in a nation-wide survey. Methods A cross-sectional study to assess national outcomes among patients with diabetes who visited 831 public hospitals in Thailand was conducted in 2013 to evaluate status of care among patients with diabetes aged at least 18 years who received medical treatment in the target hospital for the last 12 months. Results A total of 25,902 patients with diabetes were included in this study. IHD was detected among 918 patients (3.54%; 95%CI 3.32–3.77). Multivariate analysis was conducted to determine which factors were most associated with IHD, and the results showed age (AORs 1.05; 95%CI 1.04–1.05), being male (AORs 1.78; 95%CI 1.53–2.07), hypertensive comorbidity (AORs 2.10; 95%CI 1.68–2.62), being in Health Region 4 (AORs 1.93; 95%CI 1.54–2.35), presenting hyperglycemic crisis (AORs 1.53; 95%CI 1.14–2.06) and insulin therapy (AORs 1.40; 95%CI 1.17–1.66) were the highest associated factors for IHD in this population. Conclusion Our data emphasized that IHD was a problem among patients with diabetes. Diabetic patients should be regularly assessed for IHD and their risk factors should be better controlled. Moreover, the Ministry of Public Health managers and clinicians should provide further preventative strategies to attenuate cardiovascular disease.