Introduction: Ischemic heart diseases (IHD) are prevalent worldwide and they are considered a rapidly increasing common reason for death. Vitamin D3 plays a role in cardiovascular health and its deficiency is also prevalent. Objectives: To measure the prevalence of vitamin D3 deficiency among Iraqi patients with IHD and to explore any potential relation of this deficiency with other variables. Patients and Methods: Vitamin D3 level was determined among fifty patients with IHD who attended the Iraqi Center for Heart Diseases in Baghdad, to evaluate its role in this group of patients through a cross-sectional study. Results: The mean age of all participants was 55.2 ± 8.9 years, while for those with vitamin D3 deficiency was 57.55 ± 7 years. 66% of the participants were males, 82% were living in urban areas, 58% were smoking, 76% had a family history of IHD, 52% and 62% of them were hypertensive and diabetic sequentially, 58% had a high total cholesterol, 22% had a low HDL, 38% had a high LDL, and 42% had a high TG level.The vitamin D3 mean value for the ischemic participants was 21.8 ng/dl. Among those patients, 14% had sufficient vitamin D3 levels, 24% had insufficient levels, and 62% had a deficiency. Conclusion: The deficiency of vitamin D3 exists in 62% of Iraqi ischemic patients. Vitamin D3 deficiency is associated with an increased prevalence of IHD, Introduction: Ischemic heart diseases (IHD) are prevalent worldwide and they are considered a rapidly increasing common reason for death. Vitamin D3 plays a role in cardiovascular health and its deficiency is also prevalent. Objectives: To measure the prevalence of vitamin D3 deficiency among Iraqi patients with IHD and to explore any potential relation of this deficiency with other variables. Patients and Methods: Vitamin D3 level was determined among fifty patients with IHD who attended the Iraqi Center for Heart Diseases in Baghdad, to evaluate its role in this group of patients through a cross-sectional study. Results: The mean age of all participants was 55.2 ± 8.9 years, while for those with vitamin D3 deficiency was 57.55 ± 7 years. 66% of the participants were males, 82% were living in urban areas, 58% were smoking, 76% had a family history of IHD, 52% and 62% of them were hypertensive and diabetic sequentially, 58% had a high total cholesterol, 22% had a low HDL, 38% had a high LDL, and 42% had a high TG level.The vitamin D3 mean value for the ischemic participants was 21.8 ng/dl. Among those patients, 14% had sufficient vitamin D3 levels, 24% had insufficient levels, and 62% had a deficiency. Conclusion: The deficiency of vitamin D3 exists in 62% of Iraqi ischemic patients. Vitamin D3 deficiency is associated with an increased prevalence of IHD,