Background: Approximately 90% of patients with rheumatoid arthritis (RA) will have one or both knees involved during the course of the disease. Total knee arthroplasty (TKA) allows restoring function and relieving pain satisfactorily, but these patients perform in a different way than those with primary knee osteoarthritis. Aim: To evaluate the clinical and radiographic results of TKA in patients with RA. Patients and methods: We analyzed retrospectively the data of 25 posterior stabilized total knee prostheses in 19 patients, available to an average follow-up of 6 years. The scores of Hospital for Special Surgery and of the Knee Society were used for clinical assessment. Results: The mean Hospital for Special Surgery score increased from 44 points (range 27-58) preoperatively to 80 points (range 58-91) at the final follow-up examination. Two prostheses required revision and removal of the implants because of deep infection, and two had clinical failure as defined by the Knee Society score. There were no cases of implant loosening. Discussion: Even though it is not free of complications, TKA is a good choice in patients with RA in the medium term follow up, with 80% of excellent and good results in our series (Rev Méd Chile 2004; 132: 337-45).