en پژوهشي Research Introduction: Internet addiction is a global problem that caused negative effects on health. The present study aimed to determine the prevalence of Internet addiction in Iranian high school students in 2014. Materials and methods: In a cross – sectional study assessed the prevalence of Internet addiction among 381 high school students in Ilam, in 2014. The samples were selected by a multi-stage sampling method. Data was collected by a two-part questionnaire. The first part of the questionnaire was included the personal characteristics. Second part of the questionnaire was Internet Addiction Test (ITA) -20. SPSS software Package 16 was used to analyze the data. Results: Overall 75 (19.7%) students put into the Internet addiction group. Mild and moderate Internet addiction reported in 18.1% and 1.6% of all participants, respectively. There were any cases of sever Internet addiction. The mean Internet used to be 2.12 ± 2.32 and 3.57 ± 2.7 hours in non-Internet addiction and internet addiction groups, respectively (P < 0.000). The mean Internet access was 8.11 ± 6.7 and 8.2 ± 5.75 hours in non-Internet addiction and internet addiction groups, respectively. Conclusion: Internet addiction is a serious issue in teenagers. High school students possess a high danger for internet addiction. Therefore, education about the proper use of the Internet is necessary for high school students. Behavioral addiction, Ilam, Iranian high school students 39 44 http://jbrms.medilam.ac.ir/browse.php?a_code=A-10-63-2&slc_lang=en&sid=1 Ataollah Hashemian direkvand-a@medilam.ac.ir 1003194753284600510 1003194753284600510 No Ashraf Direkvand-Moghadam direkvand-a@medilam.ac.ir 1003194753284600511 1003194753284600511 Yes Ali Delpisheh direkvand-a@medilam.ac.ir 1003194753284600512 1003194753284600512 No Azadeh Direkvand-Moghadam direkvand-a@medilam.ac.ir 1003194753284600513 1003194753284600513 No Zeinab Kolivand direkvand-a@medilam.ac.ir 1003194753284600514 1003194753284600514 No