Standardized patients  as a simulation type  is one of the method  helping students to practice in safe environment with multi chances to correct errors , receive feedback  and build self–confidence . This study aimed to assess the effectiveness of using  standardized patient to teach, learn and assess students‘ clinical skills , using cohort prospective study design during two academic years 2014–2015 & 2015–2016 among fifth–year male medical students who attend Obstetrics and Gynecology rotation. Data was collected by using of 3 Tools : Pre and post–performance assessment Checklist , Mini–CEX and a satisfactory questionnaire. There was a significant difference between the two groups ( with training & without training)  in exam checklist & Mini–CEX grades( p< 0.000) .  The results of the current study provide evidence of the effectiveness of using standardized patient in teaching , learning , and assessment .