Background: Despite the great importance of public knowledge of sexually transmitted diseases such as hepatitis c virus (HCV), very few studies have been conducted in this field in Iran. Therefore, the present study determined the factors affecting the knowledge of young couples before marriage in relation to HCV.Methods: During this cross-sectional study, ۱۵۰۱ couples were assessed, out of which ۱۱۱۰ (۷۳.۹%) couples entered the study. A standard questionnaire was used to collect the data. In this questionnaire, first, the demographic characteristics of the participants such as age, gender, level of education, daily extracurricular study, and hours of mass media use were collected, followed by the main items of the study. After data gathering, they were analyzed by IBM SPSS Statistical Software Version ۲۲. Univariate analysis was used to examine the relationship between factors related to the knowledge, and multivariate analysis was used to estimate the related factors.Results: The total score of knowledge about hepatitis C was ۰.۴۹ ± ۰.۲۹. The total knowledge score for hepatitis C symptoms was ۰.۲۷± ۰.۱۹. The total score of knowledge about hepatitis C transmission routes was ۰.۳۴±۰.۲۸. The univariate analysis showed that age, level of education, history of hepatitis in a first degree relative of the family, and social networks were significantly associated with the rate of knowledge about hepatitis C (p <۰.۰۵). The multivariate analysis showed that females [(B: ۲.۱۱), CI ۹۵% (۱.۰۷_۳.۲۵), p: ۰.۰۱۴)], higher education level [(B: ۴.۰۱), CI ۹۵% (۱.۹۸_۶ .۳۳), p: ۰.۰۱۴)], history of hepatitis in a first degree relative of the family [(B: ۳.۵۶), ۹۵% CI (۱.۴۶_۵.۶۹), p: ۰.۰۱۱)] and use of social networks [ (B: ۲.۷۷), CI ۹۵% (۱.۱۱_۴.۴۸), p: ۰.۰۱۴)] were significantly associated with the rate of knowledge about HCV.Conclusion: Compared with other studies in this field, the level of knowledge about hepatitis C among young couples in Iran is alarmingly low. In health policies related to hepatitis C, more attention should be paid to the population of men, people with less than a bachelor's degree.