This is a long term follow-up study to clarify whether arthroscopic synovectomy would be able to prevent further destruction of the articular cartilage in rheumatoid joints. Three hundred and eighteen rheumatoid joints of 94 patients who had surgery in the multiple joints(average 3.4 joints per person) and was followed for an average 39.9 months (range, 24-126 months) were selected. Diagnosis of rheumatoid arthritis was made according to the 1987 revised criteria of the American College of Rheumatology. The preoperative roentgenographic narrowing of cartilage space (modified classification of ARA) and the arthroscopic findings (grading of Outerbridge) were recorded. The points of investigation were 1) further destruction of articular cartilage on X-ray, postoperatively, and 2) reaccumulation of effusion. The results were as follows; 1) Knee Joint: Among 103 knee joints there were 92 (89.3%) Stage I, G-0 knees, 8 Stage II (G-2: 1, G-3: 3, G-4: 4 joints), and 3 Stage IIIB, G-4, preoperatively. The 3 Stage IIIB, G-4 knees showed progression of narrowing of joint space and were replaced by artificial joints two years after the synovectomy. 2) Wrist joint: Fifteen joints (28.3%) out of 53 joints were Stage II, G-4, and 2 joints joints (3.8%) were Stage I, G-3, preoperatively. They were progressed to Stage IIIB at final follow-up. 3) Other Joints: There was no further narrowing of the joint space following surgery in 22 fingers, 2 toes, 34 elbows, 34 shoulders and 70 ankles. 4) Prognosis seemed to depend upon postoperative medication. From these results it would be suggested that the rate and severity of recurrence of synovitis and further destruction of articular cartilage can be decreased with early synovectomy so long as proper anti-rheumatic medication is followed, although the surgery can not halt the disease process.