Early rheumatoid arthritis patients were identified in a group of people, presenting for the first time with symptoms of joint disease. Antibodies to the rheumatoid arthritis nuclear antigen (RANA) and the early antigen of cytomegalovirus (CMV-EA) were determined in serum samples by indirect immunofluorescence. The results indicate that elevated titres of RANA antibodies are present in early rheumatoid patients, but are not a good diagnostic marker of rheumatoid disease, due to the high incidence in normal subjects and disease control patients. Strong reactions to CMV-EA were seen in a proportion of the early patients but were rare in established disease, suggesting that recent infection with this virus might be an early feature.