We have used the polymerase chain reaction (PCR) to analyse 420 normal donor blood samples taken at a city centre donation site. Three sets of human cytomegalovirus (HCMV) primers specific to the HXLF6, immediate early and late antigen gp64 genes, of the alpha, beta and gamma antigen coding regions respectively, were used to allow for the possibility of sequence variation. There was perfect correlation between the three sets of primers. Latex agglutination and enzyme-linked immunosorbent assay (ELISA) were also employed to provide data for a comparative study. The complete data show that infection with human cytomegalovirus is not only age related but is also sex related. The female population examined using PCR reached a peak infection rate of 80% by the age of 40-50 years whereas the male population reached a 98% infection rate following an almost linear increase with age. Latex agglutination data shows a similar picture although the infection rate peaks around 20% lower than with PCR. The data shows an increase in sensitivity using the PCR rather than the serology although the clinical significance of this has yet to be determined. The work presented here also demonstrates the suitability of the polymerase chain reaction as a potential diagnostic and epidemiological tool.