PURPOSE: The purpose of this study was to analyse clinical and laboratory patterns in patients in Korea with juvenile Rheumatoid Arthritis(JRA), pauciarticular type and to know the characteristics of pauciarticular JRA in Korea. METHODS: Twenty-three cases of pauciarticular juvenile rheumatoid arthritis(JRA) who were diagnosed in the department of Pediatrics, Seoul National University hospital (from june 1988 to May 1994) were reviewed. RESULTS: 1) There were 17 males and 6 females, their ages of onset were 3 years to 13 years(mean 7.3 years). 2) Knee joint was involved most frequently, and there was predominant involvement in the lower extrimities(21 patients). There were five cases that shifted to polyarticular type. 3) Two male patients were diagnosed to have iridocyclitis and treated with topical steroid without problems. 4) HLA-B27 was found in 7 male patients. 5) Low hemoglobin level was noted in three cases, platelet count was elevated in nine cases and white blood cell count was within normal range in all cases. Elevated ESR was noted in 19 cases(83%) and CRP was positive in 15 cases(65%). RF(rheumatoid factor)was positive in 1 cases and 5 cases(22%) were detected as ANA(antinuclear antibody)-positive. 6) Frequent radiological findings of arthritis were joint space narrowing, soft tissue swelling, osteopenia, osteoporosis, remodeling of joint space, and subchondral erosions. In bone scan, increased uptake in the involved joints was detected in five cases. 7) NSAIDs(nonsteroid antiinflammatory durgs) was used most freuently, and steroid was prescribed in nine patients who responded poorly to NSAIDs. 8) At onset, 21 cases (91%) were classified as functional class II and 2 cases(9%) were classified as functional class III. At last follow-up, 5 cases(22%) were classified as functional class I, 11 cases(48%) were classified as functional class II, and 7 cases(30%) were classified as functional class III. CONCLUSIONS: We evaluated clinical manifestation, disease course, and laboratory findings of 23 Korean children with pauciarticular juvenile rheumatoid arthritis. Patients were classified in functional class, which tended to be poorer in children with a polyarthric course.