Specific immunotherapy with transfer factor (TF) was used in a chronic experiment in a group of 50 female patients with rheumatoid arthritis (RA) stage I-III. The patients were followed up for 24 months, clinical and biologic examinations being repeated every 3 months. In this period the patients received beside the basic nonsteroid antiinflammatory therapy, one unit TF every week over a period of 6 months then one until TF every month (10 patients) to the end of experiment. Of the 50 patients 15 (30%) did not respond to the therapy and the experiments had to be interrupted after 6 months. Excellent, very good and good results were obtained in 35 patients (70%). In 12 patients the response was good but the dose of TF had to be increased to two units/week in the first 6 months. In 13 patients the results obtained were very good and therapy with nonsteroid products + TF was continued even after the first 6 months. In 10 patients with RA stage I the results obtained were excellent and after 6 months the nonsteroid therapy could be interrupted and the therapy was continued only with one unit TF every month. The study confirmed the fact that specific immunotherapy with TF represents an important adjuvant in the treatment of rheumatoid arthritis (RA).