Ankylosing spondylitis (AS) is a chronic inflammatory disorder of the spine and peripheral joints that can lead to significant disability if left untreated. Conventional treatments can be successful in alleviating symptoms; however, this approach has not been shown to halt the progression of disease. The proinflammatory cytokine tumor necrosis factor (TNF) is central to the pathogenesis of AS. Several anti-TNF drugs have been developed and have been shown to control symptoms effectively, and possibly to prevent both clinical and radiographic progression of disease, in patients with AS. This review discusses the data from clinical trials that have assessed the use of TNF inhibitors in patients with AS, and briefly outlines other biologic therapies that have been studied.