Objectives: The aim of the present study was to evaluate the psychometric properties of the Adult Attention-Deficit/Hyperactivity Disorder (ADHD) Self-Report Scale in Iran. Method: This was a descriptive/survey (validation) study. First, the Persian version of the ASRS was prepared using translation-back translation procedure. Then, this scale along with the Conners’ Adult ADHD Rating Scales-Self-Report: Short Version (CAARS-S: S), the Substance Abuse Attitude Survey (SAAS) questionnaire, and the Barratt Impulsiveness Scale (BIS) were administered to 330 clients (181 males and 149 females), ages 18 to 45, from counseling centers in Mashad who were selected through multistage cluster sampling procedure. In order to assess the diagnostic validity, the scale was also administered to two groups of normal (30 participants) and adults with ADHD (30 participants). Data were analyzed using SPSS statistical package and Amos Graphics. Results: Correlation analysis results showed convergent relationships between the ASRS and BIS (r=0.566, p<0.01) and SAAS (r=0.45, p<0.01) and concurrent relationship with Conners’ scale (r=0.566, p<0.01). The results of confirmatory factor analysis (CFA) revealed that all of the eighteen items had acceptable factor loadings. None of the questions were eliminated. The two factors of attention deficit and hyperactivity/impulsivity were confirmed. The analysis indicated that sensitivity of ASRS, with 50 as the cutoff point for diagnosing ADHD, is 70% and its specificity is 99%. Conclusion: The Adult ADHD Self-Report Rating Scales has sufficient validity and reliability in evaluating and assessing the problems of hyperactivity in adults.