As soon as the first clinico-epidemiology reports appeared describing an association of herpes virus infection with genital cancer, relevant questions were introduced into an ongoing follow-up of a cohort already being studied for psychosocial risk factors in cancer. The study, which was initiated in 1966, comprised 1353 persons; disease incidence was determined in 1976. Incidences of cancer (including extragenital cancer) were found to be directly related to the reported prevalence of genital herpes symptoms, but were related inversely to extragenital herpes prevalence and to previous fever episodes. With regard to the relatively common incidence of "fever blisters", i.e. facial herpes, attributed to HSV-type 1, the latter findings is less surprising than the strong association of HSV type 2 lesions with overall cancer incidence. This association was particularly noticeable in individuals who had not reported episodes of fever earlier. These findings indicate the predictive role of certain host factors which are possibly related to systematic responses of the organism, including a diminished protection against (latent) herpes genitalis infection (recurrences). Further prospective studies are needed to investigate the proper time-relationship between clinically-overt herpes genitalis and the manifestation of cancer and its possible role in provoking the recurrent eruption of latent infections.