TNF-like ligand 1A (TL1A) is a member of TNF receptor superfamily and involved in the pathogenesis of autoimmune diseases by inducing apoptosis via intracellular death domain or promoting inflammation through the activation of NFB by binding to its specific receptor death receptor 3 (DR3). Meanwhile, decoy receptor 3 (DcR3) competitively binds soluble TL1A in addition to Fas-ligand (FasL) and LIGHT and inhibits the signaling of TL1A via DR3. DcR3 overexpressed in rheumatoid synovial fibroblasts (RA-FLS) stimulated with inflammatory cytokines such as TNF or IL-1 inhibits Fas-induced apoptosis. In contrast, DcR3 inhibited cell proliferation induced by inflammatory cytokines via membrane-bound TL1A expressed on RA-FLS. Therefore, TL1A-DcR3/DR3 signaling may be involved in the pathogenesis of RA by modulating apoptosis and proliferation of RA-FLS.