Introduction Attention Deficit - Hyper Activity Disorder. (ADHD) is a heredity and psychological disorder that often continues to adulthood and causes great number of emotional, social, educationaland occupational problem for college students. Objectives We think there is a meaningful relation between ADHD and people's jobs and conditions. Aims The aim of this study isdetermine the prevalence of ADHD among students reside in hostel ofArdabil University of Medical Sciences. Methods In this cross sectional study selected all studentsin hostel of Ardabil University of Medical Sciences and all of them fill theSelf reporting Conners ADHD questionnaires and the data wereextracted and analyzed with SPSS. Results During this study the prevalence of ADHD is 8.6 percent, and themale gender shows more involvement rate than female and the involvedStudents show more incidences of smoking and psychotropic drugconsumption. Conclusions According to the high prevalence of ADHD among collegeStudents, diagnosis and treatment of ADHD as soon as possible appearsis necessary.