Background: Deficiency of vitamin D has become a global public health problem, with nearly 1 billion people worldwide being in a state of vitamin D insufficiency or deficiency. The aim of this work was to evaluate the role of hypovitaminosis D in diabetes- related anemia of chronic disease and value of its replacement in response to therapy. Methods: This randomized control trial included patients with diabetes- related anemia of chronic disease), the least Number is 318 patients. The three groups were randomized equally; group 1 was with diabetes- related anemia of chronic disease) with normal 25 hydroxy vitamin D and received treatment for anemia, group 2 was with diabetes- related anemia of chronic disease with low level of 25 hydroxy vitamin D, and group 3 was with diabetes but no anemia then follows up for hemoglobin concentration. Those Patients were informed about using vitamin D in treatment (benefits and side effects) in addition to treatment of specific anemia, then we assessed anemia after three months . Results: The study found no significant difference in age, sex, or type of diabetes mellitus (DM) between groups. However, individuals with anaemia, particularly those with low vitamin D levels, had lower serum iron and TIBC levels and higher ferritin levels. Vitamin D levels were negatively correlated with ferritin and positively correlated with iron and TIBC. HbA1C levels had negative correlations with iron, TIBC, and WBCs.Conclusions: The current study suggested that there was close relationship between vitamin D deficiency and anemia in diabetic patients.