Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 52 2 2023 01 30 399 406 Hesam Ghiasvand Warwick Evidence, Warwick Medical School, University of Warwick, Coventry, UK Jebreil Shamseddin Infectious and Tropical Diseases Research Center, Hormozgan Health Institute, Hormozgan University of Medical Sciences, Ban-dar Abbas, Iran Seyran Naghdi National Center for Health Insurance Research, Tehran, Iran Akbar Biglarian Department of Biostatistics and Epidemiology, Social Determinants of Health Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran 2021 03 03 2021 10 27 Background: HIV/AIDS is a leading cause of mortality and morbidity in Low-and-Middle-Income-Countries (LMICs). It might potentially lead to an economic burden on the health system. There is no certainty about the prevalence of HIV/AIDS in Iran. Therefore, we aimed to estimate the cost of illness of HIV/AIDS in Iran. Methods: We applied a societal perspective to capture the direct and indirect costs attributed to HIV/AIDS in Iran. We used data for age-standardized prevalence produced by the country HIV/AIDS Surveillance System for 2018. The study estimated both direct and indirect costs for a hypothetical cohort of the Iranian adult population (here equates to all registered cases with Surveillance System). For mitigating the uncertainty around the estimations, we have used an optimistic and pessimistic analysis. Results: The base case scenario showed that total direct costs and indirect costs attributed to the HIV/AIDS were US$7,946,530 and US$ 1,288,586 at the end of 2018. Moreover, the total cost is 8,785,116 US$. Conclusion: Direct costs have formed approximately 85% of total costs. The policymakers and planners should consider that these costs are only related to diagnosed or registered infected populations. These costs will be raised dramatically with increasing the diagnosed patients.   https://ijph.tums.ac.ir/index.php/ijph/article/view/24062 https://ijph.tums.ac.ir/index.php/ijph/article/download/24062/7865