en General پژوهشي Research Article Background:&nbsp;Asthma is a disease with chronic airway inflammation, whereby the airway hyper-reactivity increases. Oxidative stress balance plays a critical role in asthma.Objectives:&nbsp;The present study aimed to evaluate serum glutathione peroxidase (GPX) enzyme activity and selenium levels in patients with asthma.Methods:&nbsp;This case-control study was conducted on 64 children aged 1 - 5 years, 32 subjects as controls, and 32 subjects with asthma who were selected randomly. The serum GPX activity and selenium levels of the studied subjects were determined spectrophotometrically.Results:&nbsp;The present study showed that serum GPX activity and Selenium (Se) levels of patients with asthma were significantly lower than those of controls (P < 0.001, P < 0.05, respectively).Conclusions:&nbsp;Reduction of serum GPX activity and Se concentration in patients could have a potential role in the pathogenesis and modulation of asthma. Micronutrient supplementation of Se may be beneficial in asthma. Asthma,Oxidative Stress,Selenium,IgG,Glutathione Peroxidase 0 0 http://mcj.bums.ac.ir/browse.php?a_code=A-10-1-147&slc_lang=en&sid=1 Azardokht Tabatabaei 10031947532846002030 10031947532846002030 No Research center of Pediatric Infectious Disease, Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Iran Mohammad Babaee 10031947532846002031 10031947532846002031 No Department of Biochemistry, Iran University of Medical Sciences, Tehran , Iran Nariman Moradi 10031947532846002032 10031947532846002032 No Cellular and Molecular Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran Mohammad Nabavi 10031947532846002033 10031947532846002033 No Asthma and Allergy Research Center, Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Iran Saba Arshi 10031947532846002034 10031947532846002034 No Asthma and Allergy Research Center, Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Iran Soudabeh Fallah 10031947532846002035 10031947532846002035 Yes Department of Biochemistry, Faculty of Medicine, Iran University of Medical Sciences, Hemmat High-Way, Postal Code: 14155-5983, Tehran, Iran. Email: fallah.s@iums.ac.ir