en Health Health Original Research Original Research <p style="text-align: justify;"><strong>Background: </strong>This study aimed to assess the pattern of hygienic behaviors of Iranian children and adolescents at national and sub-national levels according to the socioeconomic status (SES) of their living region.</p> <p style="text-align: justify;"><strong>&nbsp; Methods:</strong> Data were obtained from the fourth national school-based surveillance survey entitled, &ldquo;CASPIAN-IV study&rdquo; (2011-2012). It was conducted among 14,880 students, aged 6-18 years, who were selected by multistage random cluster sampling from 30 provinces in Iran. We used the World Health Organization Global School-based Student Health Survey (WHO- GSHS) questionnaire. Data were analyzed at national and sub-national levels according to the SES of the living region.</p> <p style="text-align: justify;"><strong>&nbsp; Results:</strong> Overall, 13,486 students (49.2% girls) with the mean (SD) age of 12.50 (3.36) years participated in this study (participation rate: 90.6%). At the national level, 67.21% of the participants had daily tooth brushing, the frequencies for always washing hands after using the toilet, washing hands before eating, and washing hands with soap in school were 85.61%, 56.53%, and 50.32%, respectively.</p> <p style="text-align: justify;">The frequency of daily tooth brushing had no significant difference according to the SES of the living region. In all of the categories of washing hands, the West region (second high SES rank) had the highest frequency of hygienic behaviors (p<0.001).</p> <p style="text-align: justify;"><strong>&nbsp; Conclusion:</strong> In general, the reported hygienic behaviors were at an acceptable level; however, a large comprehensive health-promoting plan should be considered for all children and adolescents at the national and sub-national levels taking into account the disparities according to their SES.</p> Hygienic Behaviors, Tooth Brushing, Hand Washing, Children and Adolescents, Iran. 949 958 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1-1064&slc_lang=en&sid=1 Mostafa Qorbani mqorbani1379@yahoo.com 200319475328460024996 200319475328460024996 No Dietary Supplements and Probiotics Research Center, Alborz University of Medical Sciences, Karaj, Iran, & Chronic Disease Re-search Center, Endocrinology and Metabolism Population Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran. Roya Kelishadi kelishadi@med.mui.ac.ir 200319475328460024997 200319475328460024997 No Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non-communicable Disease, Isfa-han University of Medical Sciences, Isfahan, Iran. Shirin Djalalinia shdjalalinia@gmail.com 200319475328460024998 200319475328460024998 No Development of Research and Technology Center, Deputy of Research and Technology, Ministry of Health and Medical Education, Tehran, Iran. Mohammad Esmaeil Motlagh mohammad-motlagh1389@yahoo.com 200319475328460024999 200319475328460024999 No Department of Pediatrics, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Amir Kasaeian amir_kasaeian@yahoo.com 200319475328460025000 200319475328460025000 No Hematology-Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran. Gelayol Ardalan ardalan_gelayol@yahoo.com 200319475328460025001 200319475328460025001 No Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non-communicable Disease, Isfa-han University of Medical Sciences, Isfahan, Iran. Gita Shafiee gshafiee.endocrine@gmail.com 200319475328460025002 200319475328460025002 No Chronic Disease Research Center, Endocrinology and Metabolism Population Sciences Institute, Tehran University of Medical Sci-ences, Tehran, Iran. Omid Safari omidsafari@gmail.com 200319475328460025003 200319475328460025003 No Department of Pediatrics, Alborz University of Medical Sciences, Karaj, Iran. Ramin Heshmat rheshmat@tums.ac.ir 200319475328460025004 200319475328460025004 Yes Chronic Disease Research Center, Endocrinology and Metabolism Population Sciences Institute, Tehran University of Medical Sci-ences, Tehran, Iran. Sadegh Baradaran Mahdavi sadegh.b.mahdavi@gmail.com 200319475328460025005 200319475328460025005 No Medical Students' Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.