Objective:This research,investigates the prevalence of ADHD and it's subtypes among university students of Markazi province in 1389-90. Method:The method of this research was descriptive. The sample included 1773 university students (582 females,1191 males)that were selected from the population of all university students of Markazi province by implementing a random cluster sampling. The Wender Utah Rating Scale (WURS-1993)and the diagnostic Scale of Mirieskandari Revision (2008) were completed by participants. Data analysis was conducted using descriptive statistics and z test by SPSS software.Result:Results showed that the total prevalence of attention deficit/hyperactivity disorder according to WURS was 6.6% in the childhood of students and was 7.3% in their adulthood. Also the prevalence of attention-deficit,hyperactivity- impulsivity and combined type were 5.3% and 7.3%respectively.The prevalence of attention-deficit hyperactivity disorder in childhood of female students was 4.1% and in male students was 7.8%,but there was not any difference between prevalence of ADHD in adulthood between femaleand male students. Furthermore records of drop-outs,fails, psychiatric disorders and use of psychiatric drugs were more in students with ADHD.Conclusion and recommendations: These findings stress that the prevalence of ADHD is considerably high in students. In addition it revealed the importance of prevention,management and therapy of this disorder through benefiting from psychological and counseling services. This result could be beneficial for planning, budgeting, educational and therapy strategies. Making psychological and counseling services accessible in universities could prevent negative consequences of this disorder in educational and professional life.