Human herpes virus-8 (HHV-8) infections are associated with Kaposi's Sarcoma (KS), Multiple Castleman disease and primary effusion lymphoma, and particularly important in HIV/AIDS and transplantation patients. The aim of this prospective study was to detect HHV-8 prevalence in HIV-1-infected patients,in a Turkish population. A total of 85 anti-HIV-1 positive patients (53 male, 32 female; age range: 1-70 years) diagnosed at Istanbul Faculty of Medicine, Infectious Diseases and Clinical Microbiology Department were included in the study. In 45 (53%) of the patients HIV-RNA was detectable and viral loads were between 20-10.000.000 copies/ml. HHV-8-specific IgG antibodies were screened by using a commercial ELISA kit (Advanced Biotechnologies Inc, USA), and the presence of HHV-8 nucleic acids were investigated by PCR (Roche Diagnostics, Germany) in the blood samples obtained from patients. HHV-8 IgG was detected in 28.2% (24/85) of the anti-HIV-1 positive patients, and HHV-8 DNA was detected in 3.5% (3/85). One of the three HHV-8 DNA positive cases was seropositive as well. Twenty-five percent of the seropositive patients were female (6/24) and 75% were male (18/24). Of three HHV-8 DNA positive cases, two were male and one was female. The distribution of HHV-8 seropositivity rates according to the age groups were as follows; 1/3 for 1-10 years, 1/2 for 11-20 years, 3/8 for 21-30 years, 7/27 for 31-40 years, 9/30 for 41-50 years, 1/9 for 51-60 years, and 2/6 for 61-70 years. The highest seropositivity rate was detected in 41-50 age group (9/24, 37.5%), followed by 31-40 age group (7/24, 29.2%), presenting statistically significant differences between the other age groups (p< 0.05). HHV-8 DNA was detected in only 1 (4.2%) out of 24 IgG seropositive patients. HIV viral loads of the two HHV-8 seronegative patients whose HHV-8 DNA levels of < 500 copy/ml, were < 20 copy/ml and 1250 copy/ml, respectively. HIV-RNA load of the other patient with HHV-8 IgG positivity and 2240 copy/ml of HHV-8 DNA, was 191.000 copy/ml. None of the HIV-1 positive patients presented with clinical symptoms for KS. However, clinical and virological follow-up of those cases with HHV-8 IgG and/or DNA positivity would be useful to predict and control of a possible development of KS or other HHV-8-related pathologies. For a more comprehensive understanding of HHV-8 epidemiology in Turkey, multicentre studies with higher number of cases are needed.