Background & Aims of the Study: A major factor affecting health is regular physical activity. Physical activity reduces the risk of infectious diseases. The current study aimed to investigate the Perceived benefits, barriers, and self-efficacy of physical activity of the administrative staff of Shahid Beheshti University of Medical Sciences in 2018. Materials and Methods: In this descriptive-analytical study, a sample of 300 employees of the administrative staff of Shahid Beheshti University of Medical Sciences in Tehran City, Iran, was selected by a convenience sampling method. The study variables included demographic information, perceived benefits and barriers, and self-efficacy physical activity. SPSS v. 16 was used to analyze the obtained data using the Chi-squared test, Mann-Whitney U test, Kruskal- Wallis test, and Spearman correlation coefficient. Results: The collected results indicated a significant relationship between personal (P<0.03) and interpersonal (P<0.001) benefits and gender. Moreover, among the barriers, only environmental barriers had a significant relationship with gender (P<0.03). A significant association was observed between benefits and barriers and self-efficacy (P<0.01). The most common (environmental) barriers were the lack of sports space for men (51.6%) and women (62.9%), and being away from sports spaces for men (41.5%) and women (49.4%); the (personal) barriers were time-consuming for men (38.5%), women (43%). The most common benefits were better sleep for men (96.9%) and improved appearance for women (95.3%). The most general self-efficacy was exercising alone in men (61.5%) and women (56.5%). Conclusion: The staff expressed common barriers to physical activity. These barriers should be considered in designing health care policies and interventions such as providing sports facilities to promote physical activity.