AbstractBackgroundVitamin D (Vit.D) has an important role in protecting COVID‐19 patients. This study investigated the changes in vitamin D receptor (VDR) expression and interleukin 6 levels in patients with COVID‐19.Materials and methods120 hospitalized patients and 120 healthy people participated in this study, both group adjusted by sex and age. Vit.D was measured with HPLC, the expression of VDR gene was done with Real‐time PCR, and IL‐6 was measured with ELISA assay.ResultsOur findings showed no significant difference in the case of Vit.D (25‐OH‐D3) between the two studied groups, interestingly the expression of VDR was statistically lower in the patients with COVID‐19,p‐value = 0.003. VDR expression was lower in the patient with diabetes, hypertension and cardiovascular disease, significantly,p‐value = 0.002. The level of IL‐6 was statistically higher in the COVID‐19 group,p‐value = 0.003.ConclusionAlongside the important role of 25‐OH‐D3 in COVID‐19 patients, the quality and quantity of the VDR expression and its role in the level of IL‐6 are the promising risk factors in the future. Further studies are needed to determine the factors increasing the expression level of VDR, especially in the patients with diabetes, hypertension and cardiovascular disease.