Rheumatoid factor positive (seropositive) juvenile rheumatoid arthritis (JRA) is a relatively uncommon but severe form of JRA which shares clinical features with classical adult onset rheumatoid arthritis. Immunogenetic analysis of these patients supports the concept that this likely represents childhood onset of the same disease process. In this report, we review the clinical features as well as previous HLA studies of this disease. We report complete DNA based HLA typing of a small group of these patients, and discuss mechanistic implications of the results.