Certolizumab pegol, a pegylated Fab' anti-tumour necrosis factor (TNF)-α agent, has shown efficacy in patients with rheumatoid arthritis (RA) unresponsive to previous treatment. In key randomised controlled trials involving patients with moderate to severe RA and an inadequate response to methotrexate or one or more disease-modifying antirheumatic drug (DMARD), the efficacy of certolizumab pegol, as monotherapy or with methotrexate, was similar to that reported in other anti-TNF clinical studies, with 60% or fewer of patients achieving American College of Rheumatology 20% improvement in RA. Rapid clinical response was also seen, with significant differences evident at week 1, and efficacy maintained at study end and in open-label extensions. Adding certolizumab pegol to non-biological DMARDs is efficacious in other RA populations. In the CERTAIN study, certolizumab increased remission rates, prevented disease worsening and improved work productivity and daily activity in patients with low to moderate RA. In the REALISTIC study, rapid and consistent clinical responses were observed in a diverse group of anti-TNF-eligible RA patients representing those seen in clinical practice. In the RAPID studies, rapid and sustained reduction in RA signs and symptoms, inhibition of structural joint damage progression, and improved physical function were seen with certolizumab pegol plus methotrexate versus methotrexate alone in RA patients with an incomplete response to methotrexate. Certolizumab pegol was generally well-tolerated in clinical trials, although long-term observational data are not yet available. Current data suggest that certolizumab pegol suits a 'treat to target' approach, providing rapid and sustained improvements in RA signs and symptoms, and beneficial effects on workplace and home productivity in patients with RA.