The role of viral infections in the aetiology of acute and chronic arthritides of childhood is incompletely understood. The fact that some viruses cause acute arthritis is certain, although in most instances of presumed viral arthritis no agent is identified. The associations of viruses with diseases such as juvenile chronic arthritis (JCA) are limited, and have been difficult to prove with certainty. Rubella, parvovirus B19 and influenza AH2N2 have been shown by culture, serology or epidemiology to be related to at least some cases of JCA in some studies, but not in others. A rationale for pursuing investigations of viral aetiology of chronic arthritis is discussed, and a strategy involving early disease detection and close collaboration between clinicians and scientists is proposed.