BACKGROUND Little is known about HEV seroprevalence and its determinants in Iran. Considering the fact that Iran is among the countries in which HEV infection is endemic, a large-scale population-based study in this regard is justified. METHODS This survey was conducted in 2006 in Tehran and Golestan Provinces, Iran. Stored sera of subjects were tested for serological markers of anti-HEV. The baseline data were recorded in structured questionnaires. Weighted seroprevalence and weighted logistic regression coefficients were calculated. RESULTS A total of 1423 samples were included. The overall seroprevalence in two provinces was 7.4%. Age with an odds ratio equal to 1.59 (95% CI: 1.26-2.02) and history of traditional phlebotomy with an odds ratio equal to 2.28 (95% CI: 1.13-4.60) were independent predictors of HEV seropositivity. CONCLUSION Considering the high rate of HEV seroprevalence in Iran, further studies on the cost-effectiveness of vaccination among vulnerable groups are mandatory.