Clinical efficiency and safety of nimesil were studied in the multicenter open clinical trial of 52 patients with verified rheumatoid arthritis. Nimesil was given for 12 weeks in a daily dose 200-400 mg in addition to basic therapy. Clinical and laboratory parameters were assessed after 4 and 8 weeks of the treatment and after its end. The treatment produced a significant positive response of the articular syndrome. Marked improvement was registered in 11 (23.4%) patients, improvement--in 33 (79.2%) patients. Side effects were reversible and occurred in 8 (15.3%) patients. In 5 patients the drug was withdrawn. The conclusion is made on high efficiency and good tolerance of nimesil in rheumatoid arthritis patients.