Objective: Sepsis is a common cause of morbidity and mortality in the intensive care unit. Lipopolysaccharide (LPS)-induced excessive immune response is associated with multi-organ damage in sepsis. Excessive immune response causes multi-organ damage by increasing oxidative stress. Studies on the antioxidant effects of vitamin D demonstrated its protective role. In this study we aimed to investigate the effects of vitamin D on free radical metabolism in LPS injected rats.