In South Africa the association of HTLV-1 infection with myelopathy is well described in Kwa Zulu Natal, which is an endemic area for HTLV-1 infection. Japan also has a high background prevalence of HTLV-1 infection, and a significant association of HTLV-1 infection with rheumatoid arthritis has been reported. This study was undertaken to determine whether there was an association with HTLV-1 infection among black Africans with rheumatoid arthritis (RA) in Kwa Zulu Natal, South Africa. A randomly selected group of 110 black people with RA were studied. The age, sex and duration of disease were recorded and a rheumatoid factor test was performed. The presence of antibodies to HTLV-1 was assessed using an enzyme-linked immunosorbent assay. The integration of proviral DNA in peripheral blood monocytes was also studied using the polymerase chain reaction (PCR). Control data were available from a previously reported community-based study of 1018 subjects from the same geographical area. None of the 110 patients studied were positive for HTLV-1 infection by serology or by PCR. Although HTLV-1 infection is reported as a possible triggering agent for RA in Japan, we failed to detect any excess of HTLV-1 infection in black Africans with RA. Our findings are in agreement with observations in the USA and Europe.