Background: Overproduction of reactive oxygen species (ROS) and impaired iron metabolism are considered to be possible factors in the pathogenesis of Multiple sclerosis (MS). Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases are the primary sources of regulated ROS production. The NADPH oxidase (NOX) family consists of seven catalytic homologues, NOX1-5 and two dual oxidases. NOX1 and NOX5 are associated with endothelial dysfunction and inflammation but NOX4 has a protective effect on vascular function. The aims of this study were to investigate the status of NOX1, NOX4 and NOX5 and its relationship with serum iron metabolism biomarkers in relapsing-remitting MS patients.