Objective(s): Students research self-efficacy can be predict students’ tendency in research performance. Research self efficacy could help to distinguish the strength and weakness of students regarding doing research. This study aimed to evaluate psychometric properties of the research self-efficacy scale among medical post graduate students in Iran. Methods: This was a cross sectional study. 150 postgraduate students from Iran University of medical sciences took part in the study. Initial instrument was adopted from previous studies including eighteen items. Item impact score was used to assess face validity of the scale. 15 panelists evaluated content validity ratio and content validity index. Exploratory factor analysis with a sample of 150 students was performed to verify construct validity. Internal consistency (Cronbach’s alpha) and test–retest was used to verify reliability. Results: Of the original 18 items, all items showed the item impact score above 1.5, CVR above 0.49, and CVI above 0.7. The exploratory factors analysis with a minimum eigen value of 1 for each factor indicated a three-factor solution namely: problem identification, methodology; finding expression. The instrument showed 57.0% of the variance observed for research self efficacy score. Conclusion: The results indicated that the research self-efficacy scale is a valid and reliable instrument and can be used for assessing research self-efficacy among university students.