BACKGROUND Vitamin D deficiency is highly prevalent worldwide, and is also noted to be high in India. Low levels of 25(OH) D, the principle circulating storage form of vitamin D, is present in as many as one third to one half of otherwise healthy middle aged to elderly population. Endothelial dysfunction plays an important role in pathogenesis of CAD and vitamin D deficiency is postulated to promote endothelial dysfunction. Because hypovitaminosis D is prevalent and easily correctable, establishing the relationship between vitamin D and risk of acute coronary Syndrome is important. Objectives-1. To estimate vitamin D levels in IHD patients, 2) To correlate vitamin D levels with complications of IHD. MATERIALS AND METHODS A Cross Sectional study of 80 patients admitted to BLDEU's Shri B. M. Patil Medical College Hospital and Research Centre, Vijayapura between December 2014 to March 2016 with diagnosis of IHD. Patients aged more than 18 years were included in studies. The Vitamin D levels were analysed in all the patients and correlated with different parameters for statistical significance. RESULTS During our study period 80 patients were assessed as mentioned above. The mean age of our study group was 58.5 ±9.6 years. Of the study population, there were 57 male patients and 23 were females accounting to 71.2 % and 28.8 % respectively. Out of 80 patients 66 had Vitamin D deficiency in 45 were males and 21 were females. In that 34 patients had heart failure with hypotension and 1 had ventricular tachycardia, I had Left Ventricular Apical clot. CONCLUSION There is a high prevalence of Vitamin D deficiency (82.5%) among acute coronary syndrome patients. The mean age group is 58.5±9.6 years. Vitamin D deficiency is associated with increased risk of complications (75.75%) in acute coronary syndromes. Vitamin D deficiency is one of the independent risk factor for acute coronary syndrome. Vitamin D deficiency is noticed more in STEMI. Vitamin D deficiency in females was more common than compared to males.