Arthritis is reported in one-third of cases with Kawasaki syndrome. It may have an early or a late onset form. We present a 15-month-old-girl who had been referred with complaints of pain and swelling in her left shoulder. Physical examination revealed bulbar conjunctival injection, erythematous lips and pharynx, strawberry tongue, erythematous rash, edema and erythema of the left shoulder, left knee, right elbow and right wrist, and moderate distress in the left shoulder and left hip. She was diagnosed with Kawasaki syndrome, and intravenous immunoglobulin infusion (IVIG) 2 g/kg and aspirin (100 mg/kg/day) were instituted. The patient had two additional episodes of arthritis involving the hip joint on the 8th day, and the shoulder and metacarpophalangeal (MCP) and interphalangeal (IP) joints of her right hand on the 15th day. Turbid material was aspirated in both instances; Gram and Wright's staining of this material showed many leukocytes but no bacteria. A second dose of IVIG (1 g/kg) was given. At the end of the third week all extremities were painless, with a normal range of motion. Arthritis in our patient was the presenting sign, having a 'septic arthritis mimicking' and 'biphasic' pattern. Although the patient presented with severe and recurrent arthritis, which is significantly correlated with severe multisystem disease and the presence or development of coronary artery aneurysm, the response to IVIG was excellent.