The exclusive use of serology, namely immunofluorescent antibody (IFA), for the diagnosis of rodent parvovirus infection is limited to detecting IgG antibodies which develop some time after the appearance of clinical symptoms, whilst conventional viral isolation, using tissue culture, is both expensive and time consuming. Polymerase chain reaction (PCR) as a diagnostic method has the potential to overcome these problems. However, it requires detailed knowledge of the genetic code of the target organism and careful selection of the primers used. This paper describes preliminary findings in a PCR assay which detected Kilham rat virus, minute virus of mice and Toolan's H1 virus.