Abstract： Objective To determine the serum levels of B cell activating factor-receptor(BAFF-R)in patients with primary Sj(o)gren's syndrome(pSS)and investigate the role of BAFF-R in the pathogenesis of pSS.Methods The serum concentration of BAFF-R was measured by ELISA in 120 patients with pSS and 62 age-and sex-matched normal controls.Results The median level of serum BAFF-R was(692.7 ± 536.9)ng/L in pSS and (279.7 ± 186.9)ng/L in healthy controls.The serum level of BAFF-R in the pSS was significantly higher than normal controls(P ＜0.01).Higher level of BAFF-R was associated with higher level of IgG(r =0.429,P ＜0.01).Serum level of BAFF-R had no correlation with IgA,IgM,C3,C4,RF,ESR and CRP.BAFF-R level was markedly increased in patients with positive ANA,anti-SSA,anti-SSB antibody compared with those with negative antibody.Conclusion The serum BAFF-R level was significantly elevated and correlated with the level of immunoglobulin and autoantibodies.BAFF-R play certain role in the pathogenesis of pSS.