Presumed apathogenic viruses have been suggested to play a role in HIV infection. In some cohorts of HIVpositive patients, GB virus C (GBVC) has been associated with prolonged survival and time to AIDS. We set out to address whether GBVC infection had any influence on survival in a cohort of 112 homosexual white HIV-1 positive Danish men. Patients were enrolled between 1984 and 1987 and followed for a mean of 6.7 years. Follow-up was censored in May 1996 when the first patient in the cohort received HAART. Plasma samples were screened at baseline using polymerase chain reaction methods for GBVC. Of the 112 patients, 27 (24%) were positive for GBVC. No difference in time to AIDS or death was observed between the GBVCnegative and -positive patients. Furthermore, no difference in CD4+ T cell decline was observed in the first year following blood sampling between the GBVC-positive and -negative groups