Objective To examine the expression variation of toll-like receptor 2 (TLR 2)in peripheral blood monocytes of patients with rheumatoid arthritis (RA)and explore its role in pathogenesis of RA.Methods Mean fluorescence intensity of TLR 2 expression on the surface of peripheral blood monocytes were detected by flow cytometry and independent samples t-test was used for statistical analysis.Results Mean fluorescence intensity of TLR 2 expression on the surface of peripheral blood CD14+ CD45+ cell of RA patients was 357.68±86.97,while in normal control it was 223.71±87.70.It indicates that the expression of TLR 2 on peripheral blood monocytes in patients with active disease was higher than in normal indi-viduals (t=5.478,P=0.005,P<0.01).Conclusion Increase of the TLR 2 expression on peripheral blood monocytes in patients with active disease suggests its import role in pathogenesis of RA.