The clinical course of 48 patients with primary SS has been reviewed with particular reference to the articular manifestations. The incidence of arthritis and/or arthralgia was 54%. In a third of these patients it was a presenting feature and preceded sicca symptoms. The arthropathy tended to be polyarticular, the most frequent joint involved being the knee. It was symmetrical in 55% of cases. Joint symptoms or signs were intermittent, lasting less than a month in 55% of cases. The acute onset of purpuric vasculitis was associated with an acute arthritis in four out of the nine patients with such a vasculitis. Joint deformity was unusual, ulnar deviation occurring in only six patients. Hand X-rays obtained from primary SS patients revealed evidence of joint erosions in 33% of PIP joints, 27% of MCP joints and 12% of wrist joints.