International Journal of Preventive Medicine (Int J Prev Med)2008-7802002015021714801480EN20150217<strong>Background:</strong> The purpose of this study was to evaluate the validity and reliability on the Persian translation of the Modifable Activity Questionnaire (MAQ) in a sample of Tehranian adolescents.<br /><strong>Methods:</strong> Of a total of 52 subjects, a sub‑sample of 40 participations (55.0% boys) was used to assess the reliability and the validity of the physical activity questionnaire. The reliability of the two MAQs was calculated by intraclass correlation coeffcients, and validation was evaluated using <br />Pearson correlation coeffcients to compare data between mean of the two MAQs and mean of four physical activity records.<br /><strong>Results:</strong> Intraclass correlation coeffcient was calculated to assess the reliability between two MAQs and&nbsp; the&nbsp; results of&nbsp; leisure&nbsp; time physical activity over&nbsp; the past year were 0.97. Pearson correlation coeffcients between mean of two MAQs and mean of four physical activity records were 0.49 (P &lt; 0.001), for leisure time physical activities.<br /><strong>Conclusions: </strong>High reliability and relatively moderate validity were found for the Persian translation of&nbsp; the MAQ&nbsp; in a Tehranian adolescent population. Further studies with&nbsp; large sample size are suggested to assess the validity more precisely.<br /><strong>Keywords:</strong> Persian, physical activity, questionnaire, reliability and validityhttp://ijpm.mui.ac.ir/index.php/ijpm/article/view/1480http://ijpm.mui.ac.ir/index.php/ijpm/article/download/1480/1764