Human herpesvirus 8 (HHV-8), classified in Herpesviridae family, is the etiological agent of Kaposi's sarcoma (KS), primary effusion lymphoma and multicentric Castleman's disease. In contrast to the other herpesviruses, HHV-8 seroprevalence is low in general populations; however, the higher prevalence observed in individuals with immunodeficiencies such as AIDS poses an increased risk for KS. The global distribution of HHV-8 shows great variations, with the highest seroprevalence seen in Africa. The number of studies on the seroprevalence of HHV-8 in Turkey are limited. The aim of this study was to determine the HHV-8 seroprevalences in healthy blood donors and HIV-positive patients, that will contribute HHV-8 seroepidemiological data in our country. This study was designed as a cross-sectional study. A total of 551 healthy donors (76 female, 475 male; age range: 18-65 years) admitted to Ege University Medical School Hospital, Blood Center for blood donation between December 2013-January 2014, and 173 HIV-positive patients (30 female, 143 male; age range: 18-65 years) admitted to infectious diseases outpatient clinic between October 2013-January 2014, were included in the study. A commercial ELISA method (KSHV/HHV-8 IgG ELISA Kit, Advanced Biotechnologies Inc, USA) was used for the detection of IgG antibodies that were structured against HHV-8 lytic antigens. In the study, 29 (29/551, 5.3%) of blood donors and 44 (44/173, 25.4%) of HIV-positive patients, with a total of 73 (73/724, 10.1%) cases were found as HHV-8 seropositive. The difference between blood donors and HIV-positive patients in terms of HHV-8 seropositivity rates was statistically significant (5.3% versus 25.4%; p<0.05). In both of the study groups, no statistically significant difference was detected between HHV-8 seropositivity with gender and age. When considering HIV-positive patients, no statistically significant difference was observed between HHV-8 seropositivity with the duration of anti-HIV positivity, CD4(+) T cell count, HIV-RNA status and history of having sexually transmitted disease. As a result, HHV-8 seroprevalence rate detected in our study is similar to the data of other studies performed in Turkey, as well as the rates reported from other European and Asian countries.