A number of studies have emphasized the critical role of TNF-a in the pathogenesis of rheumatoid arthritis (RA). New therapeutics called "bilologicals" have been recently admitted for treatment of RA, including infliximab and etanercept, also in Japan. Of note, fully human anti-TNF a monoclonal antibodies, adalimumab and golimumab, have been developed to overcome several major problems resulting from the chimeric natures of infliximab. The efficacy and safety of adalimumab have been demonstrated in several clinical trials, as highlighted in this review. Thus, adalimumab has already been approved for treatment of RA in the United States and European Union. The clinical trials of another fully human anti-TNF-alpha monoclonal antibody golimumab are now under way.