Epidemiological data indicate a sexual route of transmission of acquired immune deficiency syndrome (AIDS) associated Kaposi's sarcoma. Recently human herpes virus 8 (HHV-8) has been proposed as the aetiological agent for development of Kaposi's sarcoma. Further the virus has been reported in semen obtained from healthy men. In Denmark strict biochemical and microbiological criteria are used in combination with an intensive interview to select semen donors. Despite these strict criteria, HHV-8 may be transmitted to a recipient and even the child by the use of donor semen. We used four different polymerase chain reaction (PCR) and one nested PCR to test semen from 100 Danish donors for the presence of HHV-8 DNA. All 100 samples were consistently negative for HHV-8 DNA, while only one sample (1%) was positive for cytomegalovirus DNA. As HHV-8 was not demonstrated in any of the semen samples, we conclude that the frequency of HHV-8 in semen from Danish donors is very low.