The association of HIV infection with rheumatic syndromes is reviewed, with emphasis on the specific differences between the rheumatic diseases in their idiopathic form compared with their occurrence with HIV infection. Alterations in presentation, pathogenesis and treatment are stressed. The first section of the article concentrates on joint and articular involvement, and the second on autoimmune phenomenon in relation to lymphatic organs, muscle and vasculature. Wherever possible, the direct effect of the HIV organism or its effect on the immune system modifying or contributing to the aetiology of each disease is discussed. HIV infection has many manifestations, and involvement of the musculoskeletal system is not uncommon. Various infections of bone, joint and muscle have been described, which is not surprising considering the immunodeficiency associated with HIV. Reiter's syndrome and the seronegative arthropathies and reactive arthritides also may be expected, particularly with the possible occurrence with sexually transmitted organisms. New onset of psoriasis in an adult should prompt the physician to consider HIV infection in the differential diagnosis. Perhaps more surprising is the occurrence of autoimmune diseases in association with HIV. However, as will be described, some of the associations such as rheumatoid arthritis and HIV are controversial and we attempt to describe current theories on pathogenesis, recognising that much more investigation is needed before we have a complete understanding of this disease.