Rheumatoid arthritis (RA) is a chronic inflammatory disease that results in significant functional disability [1], work disability [2,3], and mortality [4]. It has long been apparent that the risk of certain malignancies is increased in people with RA. Part of this increased risk may be related to the disease itself, but there is also concern that chronic treatment with immunosuppressive medications may influence this risk. This article reviews the occurrence of malignancies in RA, discusses possible etiological explanations, and looks at the currently available data on the influence of disease-modifying antirheumatic drugs (DMARDs) and biological therapies on this risk.