Despite the clinical importance of the human cytomegalovirus (CMV) infections especially in pregnant women and immunocompromised patients, there are only a few CMV seroprevalence studies in certain risk groups from Hungary. In this study, the results of CMV-specific IgG antibody tests were analysed by calendar year, gender, and 5-year age groups (from 0 to 97) among the population of South Transdanubia, Hungary from blood samples (N = 13,777), between January 1, 2010, and December 31, 2024, covering 15-years. The average CMV-specific IgG seropositivity was 69.2% (9,522/13,761 patients), which increased with age between 31 and 50 years (+~1%/year). Seroprevalence was lowest (37.8%) in the 1-5 age group, reached 50% in the 21-25 age group, and exceeded 80% in those over 50 years. In certain age groups (16-20, 26-30, 46-50, 51-55, and 66-70 years old), CMV seroprevalence was significantly higher among women. Women of child-bearing age between 16 and 45 years showed 61.2% seroprevalence. Between 2020 and 2023, the yearly CMV seroprevalence decreased (from 70.8 to 64.7%) by ~6%. This summary of CMV IgG seroprevalence fills gaps in terms of both the number of elements, the size of the studied population, and its age diversity in Hungary. The average CMV seropositivity in South Transdanubia follows the level of socio-economic development of the countries. Basic knowledge of CMV seroepidemiological data helps physicians with CMV risk assessment and find the optimal infection prevention strategies in different age and sex groups.  Kulcsszavak: cytomegalovirus, CMV, seroepidemiology, Hungary