Cytomegalovirus (CMV) is a type of herpes virus. This virus is one of the most common causes of congenital and prenatal infections. CMV infection in pregnant women, especially in the first trimester, may lead to congenital abnormalities in newborns. The prevalence of CMV infection in developed countries is approximately 40%, and in developing countries, this prevalence may be up to 100%. Because there is no information available related to the seroepidemiological patterns of this infection in different cities of Alborz province, Iran, this study was conducted. This seroprevalence study was based on sera collected from adults who were referred to health care providers or Medical Diagnostic Laboratory Centers (MDLS) in Alborz province, Iran, from 2011 to 2015 for different purposes. Using ELISA (IgG), a retrospective serological survey of CMV antibodies in serum samples was performed in a non-immunized community. Frozen sera from 2001 individuals who were randomly selected by a cluster sampling technique were collected from spring 2013 to winter 2015. Seroprevalence was stratified by age (>1 to <50 years). Mathematical techniques were used to determine whether there is a relationship between CMV seroprevalence and age, sex, and level of education in this community. Data were analyzed using Fisher’ s exact test and the χ 2 test using SPSS software version 11. 5. The mean age of seropositive individuals varied between 15 and 50 years. CMV IgG was found in 1813 (91%) of 2001 individuals. In total, 188 individuals (9%) were negative for CMV IgG. There were significant relationships between seropositivity (CMV IgG) and age, sex, level of education, and level of antibody titer by sex. As in other developing countries, the prevalence of CMV infection in adults in Alborz province is high. Since CMV infection is prevalent and there are potential abnormalities associated with it, we strongly recommend the expansion of preventive measures and the establishment of programs to inform at-risk populations, especially vulnerable populations such as transplant recipients, immunocompromised patients, and school children on how to prevent this infection and its associated consequences.