Certolizumab pegol (Cimzia®) is a recombinant, polyethylene glycolylated, antigen-binding fragment of a humanized monoclonal antibody that selectively targets and neutralizes tumour necrosis factor (TNF)-α. The drug is indicated for subcutaneous use every 2 or 4 weeks (q2w or q4w) for the treatment of adults with moderate to severe active rheumatoid arthritis (RA). The efficacy of subcutaneous certolizumab pegol in adults with active RA has been investigated in several well designed, placebo-controlled trials. In four pivotal studies of ≤52 weeks duration, patients with moderate to severe disease receiving recommended dosages of certolizumab pegol (200 mg q2w or 400 mg q4w), either as monotherapy (after failing prior disease-modifying anti-rheumatic drug [DMARD] therapy) or in combination with methotrexate (after responding inadequately to methotrexate alone), experienced rapid clinical improvement, with some combination trials also demonstrating inhibition of radiographic progression. The beneficial effects of certolizumab pegol therapy were generally maintained for up to ≈5 years in clinical trial extensions in which the drug was administered at dosages of 400 mg q4w or q2w. Additional studies suggest certolizumab pegol is also effective in patients who are Asian or have low to moderate disease activity, as well as more clinically representative patient populations. The tolerability profile of certolizumab pegol was acceptable, with infections/infestations the most common adverse events. Thus, certolizumab pegol is an effective option for the management of active RA in adults, although additional long-term and comparative efficacy and tolerability data are needed to help definitively position certolizumab pegol relative to other biological DMARDs, particularly other anti-TNF agents.