Synovectomy of the knee in rheumatoid arthritis has been recommended as an effective procedure which improved symptoms such as pain, swelling, and limitation of motion. But some problems, such as limitation of range of motion, infection, long hospital days, occured in open synovectomy. Arthroscopic synovectomy yields reliable result compatible to open synovectomy with less invasiveness and postoperative morbidity. The authors analyzed 20 knees of 14 patients who has done synovectomy of knee in Kyung Hee University Hospital from September 1989 to October 1992. Of the 14 patients, thirteen were females and only one was male, ten knees were affected on the right and ten on the left respectively. Five knees were operated as open synovectomy and fifteen knees as arthroscopic synovectomy. In six patients, both knees were operated either open or arthroscopic synovectomies. The preoperative diagnosis of 20 knees were rheumatoid arthritis as clinically, serologically and radiologically, 13 knees are confirmed as pathologically. Average hospital days after operation were 19 days in open synevectomy and 11 days in arthroscopic synovectomy. Average operation time were 72 minutes in open synovectomy and 84 minutes in arthroscopic synovectomy. No complication occured as a result of these synovectomies. After average follow up of 19 monthes, 1 knee from 5 knees in open synovectomy and 3 knees from 15 knees in arthroscopic synovectomy had pain and intermittent swelling as postoperatively. And only 1 knee in open synovectomy had loss of range of motion. No other patients lost motion in their knees. Preoperatively 17 knees showed radiographic change of rheumatoid arthritis and 16 knees showed no progressive radiographic deterioration at final follow up. And patients overall showed a significiantly increased functional status postoperatively. In conclusion, the result obtained after arthroscopic synovectomy are comparable with those obtained after open synovectomy. In addition arthroscopic procedure had lessened postoperative morbidity as loss of range of motion, postoperative infection, long hospital days and useful as palliative surgery in advanced rheumatoid arthritis.