MSc (Microbiology) / Department of Microbiology / Background: Human Herpes Virus-8 (HHV-8) and Human Immunodeficiency Virus (HIV) are endemic in sub-Saharan Africa. However, the prevalence of HHV-8 in HIV-infected individuals in sub-Saharan Africa has not been fully described and characterized. Objectives: The objective of this study was to determine the seroprevalence and genetic subtypes of HHV-8 in an HIV-infected population in Cameroon. Methodology: KSHV/HHV-8 Enzyme-linked Immunosorbent Assay (ELISA) kit (Advanced Biotechnologies Inc., USA) was used to detect IgG antibodies in the plasma of 406 HIV-infected outpatients of the Mutengene Baptist Health Centre, Cameroon. To detect the viral presence, a 233 bp fragment of the ORF 26 gene of HHV-8 was targeted by polymerase chain reaction (PCR) in total DNA purified from patients’ whole blood. A 453 bp of the K1 gene was amplified by nested PCR, sequenced and phylogenetically analysed to infer subtypes. The online tool, Synonymous Non-synonymous Analysis Program (SNAP), was used to determine the rate of synonymous and nonsynonymous mutations in the K1 gene. The genetic variability among the derived K1 nucleotide sequences was determined by mean genetic distance analysis. Results: Of the 406 participants, an HHV-8 seroprevalence of 79.1% was obtained. There was a statistically significant association of seroprevalence with age (p= 0.00), CD4+ cell count (p= 0.02), marital status (p= 0.02) and ownership of a transistor radio set (p= 0.00). Seventy samples (23.3%) were successfully amplified for ORF 26 gene confirming the presence of replicating virus. K1 sequences were obtained for 14 of the 20 (70%) K1 amplified DNAs. The mean genetic diversity of K1 sequences ranges from 0.0%-22.3%. Phylogenetic analysis revealed two infecting viral subtypes in the study cohort: subtype A5 (57.1%), and subtype B (35.7%). Greater positive selection and genetic diversity were observed in A5 subtype compared to B subtype of K1. Interestingly, one sample (BM 547) clustered with an unclassifiable sequence from South Africa. Conclusions and recommendation: This study revealed the endemicity of HHV-8 infection in the studied population, with subtypes A5 and B as the most important epidemiological genetic variants. In addition, targeting the ORF 26 region by PCR could be an approach to detect replicating virus in individuals. Further studies should investigate the association between HHV-8 infection and KS development in the study area which is endemic for HIV. This study contributes data to the HIV/HHV-8 co-infection landscape in the study area and in Africa at large.