We investigated the role of vitamin D on glycemic regulation and cardiac complications in patients with type 2 diabetes mellitus (T2DM). A total of 1139 patients (49.3% males vs 50.7% females) were included. Information on sociodemographic lifestyle, family history, blood pressure (BP), and coronary heart disease (CHD) complications was collected. Significant differences were found between males and females regarding age-groups (P= .002), body mass index (BMI;P= .008), physical activity (P= .010), sheesha smoking (P= .016), cigarette smoking (P= .002), hypertension (P= .050), metabolic syndrome (P= .026), and CHD (P= .020). There were significant differences between vitamin D deficiency, insufficiency, and sufficiency in relation to age-group (P= .002), income (P= .002), waist circumference (P= .002), hip circumference (P= .028), waist-hip ratio (P= .002), and BMI (P= .002). Further, mean values of hemoglobin, magnesium, creatinine, hemoglobin A(1c)(HbA(1c)), total cholesterol, uric acid, and diastolic BP were significantly higher among patients with vitamin D deficiency compared with those with insufficiency and sufficiency. Multiple logistic regression analysis revealed that 25-hydroxy vitamin D, 25(OH)D, HbA(1c), waist circumference, uric acid, duration of T2DM, total cholesterol, systolic and diastolic BP, and BMI were strong predictor risk factors for CHD among patients with T2DM. The present study supports that 25(OH)D may have a direct effect on CHD and on its risk factors.