OBJECTIVE To investigate the long-term efficacy of rehabilitation following arthroscopic synovectomy in patients with rheumatoid arthritis treated with biologic agents. METHODS Arthroscopic synovectomy was performed in 29 joints of 17 patients, which were divided into two groups. Group 1 included arthroscopic synovectomy plus rehabilitation for 19 joints in 10 patients, and group 2 included arthroscopic synovectomy without rehabilitation for 10 joints in 7 patients. The Disease Activity Score C-reactive protein (DAS28-CRP), Health Assessment Questionnaire-Disability Index (HAQ-DI), and Functional Independence Measure (FIM) values (motor subscale) at 9.7 years after arthroscopic synovectomy were evaluated to identify the clinical factors related to outcomes. RESULTS The increase in FIM score was significant in group 1 (p=0.05). HAQ-DI at 9 years was significantly decreased in group 1 (p=0.02). Therefore, arthroscopic synovectomy with rehabilitation was significant in improving FIM and HAQ-DI scores over a long period. Multiple regression analysis of FIM scores at 9 years indicated that rehabilitation (p=0.03) and disease duration (p=0.02) were significantly related to outcomes. FIM score at 9 years was significantly negatively correlated with disease duration (p=0.01, r=-0.58, Y=88.89-0.21X). CONCLUSIONS Rehabilitation following arthroscopic synovectomy was effective in achieving high FIM scores over time in patients with rheumatoid arthritis.