en Health Health Original Research Original Research <strong>Background: </strong>Development of tools for measuring stress has been considered by mental health researchers for many years. The purpose of this study was to develop and validate a &quot;Stressful Events Inventory&quot;(SEI) using exploratory and confirmatory factor analyses.<br> &nbsp;&nbsp; <strong>Methods:</strong> Using a representative sample (n=6000) from all people who reside in Tehran, the validity of the inventory was confirmed by exploratory and confirmatory factor analyses, and its reliability was also confirmed by Cronbach&#39;s alpha.<br> &nbsp;&nbsp; <strong>Results: </strong>Eleven major sets of stressful events were identified as follow: political problems (&alpha;=0.731), neighborhood&rsquo;s problems&nbsp; (&alpha;=0.739), livelihood problems (&alpha;=0.609), fear of the future (&alpha;=0.663), educational events (&alpha;=0.635), educational changes (&alpha;=0.704), individual changes (&alpha;=0.463), occupational difficulties (&alpha;=0.64), housing problems (&alpha;=0.69), problems related to occupational relations (&alpha;=0.46), and family problems (&alpha;=0.69). The value of correlation between the factors was equal to 0.82 and the value of variance determined by these factors was 0.49 (r^2=0.49). In the confirmatory factor analysis, these factors also had an appropriate fitness (RMSEA=0.02).<br> &nbsp;&nbsp; <strong>Conclusion:</strong> The developed instrument has suitable psychometric properties, which make it appropriate for future research on psychosocial stress. Stress, Stressful event inventory, Exploratory factor analysis, Confirmatory factor analysis 337 343 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-4710-1&slc_lang=en&sid=1 Fateh Tavangar fatehtavangar@gmail.com 200319475328460063961 200319475328460063961 No Department of Social Welfare Management, & Social Welfare Management Research Center, University of Social Welfare and Rehabilitation Science, Tehran, Iran Hassan Rafiey ha.rafiey@uswr.ac.ir 200319475328460063962 200319475328460063962 Yes Department of Social Welfare Management, & Social Welfare Management Research Center, University of Social Welfare and Rehabilitation Science, Tehran, Iran Ahmad Ali Noorbala noorbala1@gmail.com 200319475328460063963 200319475328460063963 No Psychosomatic Medicine Research Center, Tehran University of Medical Science, Tehran, Iran Farhad Nosrati Nejad farhad.nosrati@gmail.com 200319475328460063964 200319475328460063964 No Social Determinants of Health Research Center, University of Social Welfare and Rehabilitation Science, Tehran, Iran Gholamreza Ghaedamini Harouni qaedamini@gmail.com 200319475328460063965 200319475328460063965 No Department of Social Welfare Management, & Social Welfare Management Research Center, University of Social Welfare and Rehabilitation Science, Tehran, Iran Hesam Ghiasvand hesambs82@gmail.com 200319475328460063966 200319475328460063966 No Social Determinants of Health Research Center, University of Social Welfare and Rehabilitation Science, Tehran, Iran Fardin Alipour barbodalipour@gmail.com 200319475328460063967 200319475328460063967 No Social Work Department, University of Social Welfare and Rehabilitation Science, Tehran, Iran Sina Ahmadi sinaahmadi@gmail.com 200319475328460063968 200319475328460063968 No Department of Social Welfare Management, & Social Welfare Management Research Center, University of Social Welfare and Rehabilitation Science, Tehran, Iran