Some experts have defined vitamin D deficiency as a serum 25(OH)D level <20 ng/mL and insufficiency as between 21 and 29 ng/mL: a target of >30 ng/mL is suggested for optimal health. However, this remains controversial because of the lack of a consensus regarding the optimal range for serum 25(OH)D. Nevertheless, there is a common understanding that low serum 25(OH)D levels cause a negative calcium balance, secondary hyperparathyroidism (SHPT), and bone disease. Impaired metabolism of vitamin D is a common feature of chronic kidney disease (CKD). Renal dysfunction is associated with impaired conversion of 25(OH)D to 1,25(OH)2D. Therefore, supplementation with active vitamin D [1,25(OH)2D] is commonly practiced in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). However, recently it has been shown that 25(OH)D can be converted to 1,25(OH)2D at sites other than the kidney, including the prostate, breast, colon, and macrophages. Patients on hemodialysis have increased level of inflammatory mediators including C- reactive protein, tumor necrosis factor and IL6, as it plays major role in malnutrition, inflammation and atherosclerosis as well as overall mortality rate in these patients. Leukocytes are considered among the classic inflammatory markers due to their role in pathogenesis of atherosclerosis and its complications by mediating several biochemical pathways. The association between inflammatory markers and cardiovascular events, coronary artery disease and its complications occur with high frequency in patients with ESRD; and substantially is contributing to cardiovascular morbidity and mortality in this population. Elevated levels of serum CRP is linked to the development of coronary artery disease even in the absence of dyslipidemia. Serum CRP level measured by conventional method is a predictor of mortality in hemodialysis patients.