Background: Out-of-pocket and informal payments are considered as 2 most important topics for equity in health care financing. Therfore, this study was conducted to systematically review and meta-analyze the status of these payments in Iran's health care system.
   Methods: Required data were collected through searching the following key terms: "Unofficial", "Informal Payment", "Iran", "Health Financing", "Health expenditure", and "Out-of-pocket" on Scopus, PubMed, IranMedex, SID, and Google Scholar databases. After extracting and screening previous studies, data were collected from the articles using PRISMA pattern. To perform the meta-analysis, Comprehensive Meta-Analysis (CMA: 2) software was used. 
   Results: A total of 15 studies were entered in this review. Overall, the rate of out-of-pocket payments was estimated to be 50% (95% CI: 45-57%). A significant correlation was found between gender and the rate of out-of-pocket payments (p≤0.05).  Moreover, the overall rate of informal payments was found to be 35%.  Most of the informal payments were in form of cash, and the main reasons for informal payments were appreciating the staff and medical team as well as requests made by the hospital staff. Length of stay, marital status, employment status, income, and insurance coverage were key factors in the field of informal payments.  
   Conclusion: According to the results of the present study, out-of-pocket and informal payments are more prevalent in Iran. Considering the negative effects of these payments on the health care system, it is of prime importance to implement extensive interventions to reduce or even prevent these payments.