en General پژوهشي Research Article Background: Policy-makers in the Ministry of Health Care and Medical Education need to have knowledge concerning high-risk behaviors among medical students in order to have positive changes in the educational system of universities of medical sciences. Objectives: To enquire into the prevalence of high risk behaviors among medical students. Methods: A cross-sectional study was conducted on medical students in one of the largest medical universities in Tehran, Iran. A total of 275 medical students participated in the study. They filled out a self-developed questionnaire that covered both demographic characteristics and items on eight main risk domains including safety, violence, depressed mood, physical activity, nutrition, smoking, alcohol consumption, and substance abuse. Results: A total of 275 students (55.3% male, mean age: 23.7 ± 4.3 years) took part in the study. Approximately, 38% of the subjects reported less than 30 minutes of low intensity physical activity during the preceding week. Obesity and overweight were seen in 24.4% of the participants. Around 8% of the students had body mass index (BMI) values below 18 kg/m2. Daily smoking during the past month was reported by 10.5%. A total of 29 students (10.2%) mentioned drinking alcohol during the past month. Sense of depression and hopelessness were reported by 26.6% of students. A total of 5.5% had seriously considered committing suicide, with 3.6% who had actually attempted, with some doing it more than once. Conclusions: In this study, physical inactivity, obesity/overweight, and depressed mood were more frequent. Smoking, alcohol consumption, and drug abuse were more prevalent among male students. Medical Student,Health Risk Behavior,Cigarette Smoking,Violence 0 0 http://mcj.bums.ac.ir/browse.php?a_code=A-10-1-103&slc_lang=en&sid=1 Zahra Sorush 10031947532846002227 10031947532846002227 No Department of Community Medicine, Preventive Medicine and Public Health Research Center, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran Fereydoon Sajadi 10031947532846002228 10031947532846002228 No School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran Behnaz Soleimani Tapehsari 10031947532846002229 10031947532846002229 No Department of Community Medicine, Preventive Medicine and Public Health Research Center, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran Arghavan Haj-Sheykholeslami 10031947532846002230 10031947532846002230 No Department of Community Medicine, Preventive Medicine and Public Health Research Center, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran Fatemeh Nadimi G.G 10031947532846002231 10031947532846002231 No Department of Community Medicine, Preventive Medicine and Public Health Research Center, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran Hossein Dehghani 10031947532846002232 10031947532846002232 No Department of Molecular Medicine, School of Medicine, Birjand University of Medical Sciences (BUMS), Birjand, Iran Marzieh Nojomi 10031947532846002233 10031947532846002233 Yes Professor of Community Medicine, Department of Community Medicine, Preventive Medicine and Public Health Research Center, School of Medicine, Iran University of Medical Sciences (IUMS), P.O.Box: 14155-5983, Tehran, Iran. Tel: +98-2188602225, Fax: +98-2188602217, Email: mnojomi@gmail.com