Context: Hepatitis delta virus (HDV) leads to the most severe form of chronic viral hepatitis.Objectives: To determine the prevalence of HDV and create pooled estimations of possible risk factors, a systematic review was conducted to collect all epidemiological studies on HDV among chronic hepatitis B patients in Iran.Data Sources: In this systematic review, databases such as pubMed, embase, ISI, Google scholar, and Iranian databases (MagIran, Iranmedex, and SID) were searched.Study Selection: Studies that clearly stated information about the number of HBsAg positive patients infected with HDV were selected.Data Extraction: The name of the city, the author’s name, year of study, HDV detection method, sample size, HBsAg positive frequency, mean age, total prevalence of HDV, and risk factors were extracted.Results: The pooled HDV prevalence was 7.8% (95% CI: 5.89-9.71). In the survey-data analysis, HDV prevalence was 6.61%. HDV prevalence was 30.47% (95% CI: 9.76 to 51.19), 14.4% (95% CI: 7.72 to 21.07), and 4.94% (95% CI: 3.73 to 6.15) in cirrhotic, chronic-hepatitis, and inactivecarrier patients, respectively. pooled oRs were calculated for several factors common to Iranian HBsAg-positive patients, including history of blood transfusion (oR: 1.1 (95% CI: 0.40 to 2.98)), intravenous drug abuse (oR: 1.6 (95% CI: 0.78 to 3.21)), previous hemodialysis (oR: 1.72 (95% CI: 0.79 to 3.76)), and HBeAg-positive status (oR: 1.26 (95% CI: 0.66 to 2.4)).Conclusions: The prevalence of HDV is less common in Iran than in endemic regions such as Italy and Turkey, however, it is a severe form of hepatitis in HBsAg-positive patients. The most probable route of HDV transmission is hematologic, which suggests the importance of blood screening for HDV, especially in groups with numerous blood transfusions.