Long-term extension studies and observational drug registers have revealed an increased risk of serious infections in patients treated with anti-tumor necrosis factor agents, particularly infliximab, etanercept and adalimumab. The same may be true for the newer biological drugs rituximab, tocilizumab and abatacept, although this has yet to be confirmed by long-term observational studies. We review the risk of tuberculosis, herpes zoster and other opportunistic infections, and the recommendations for screening for tuberculosis and hepatitis B and C infections in patients affected by rheumatoid arthritis, with the aim of informing patients and encouraging greater awareness among physicians.