Tumour necrosis factor inhibitors have demonstrated significant clinical and radiological benefits in rheumatoid arthritis (RA). However, they have important adverse effects including an association with infection. Results from current studies, including meta-analyses of randomized controlled trials and observational studies, are conflicting regarding the risk of serious infection in RA patients treated with TNF inhibitors. The majority of data suggest an increased risk, in particular of respiratory, skin and soft tissue infections, including tuberculosis. This increased risk of tuberculosis is of particular concern in the APLAR region. However, adverse event analysis remains a difficult area to study and decisions regarding initiation of TNF inhibitors must be made on a case-by-case basis after carefully considering the risks and benefits. ; Veera S. Katikireddi, Samuel L. Whittle and Catherine L. Hill