Recently, biologic agents have become available for the treatment of rheumatoid arthritis. Such agents, the so-called TNF blockers, selectively inhibit TNF alpha, a dominant proinflammatory cytokine. They allow good suppression of the disease activity in many patients. Even in nonresponders to conventional disease modifying antirheumatic drugs (DMARDs) a good response may be achieved. The anti-erosive effect appears to be excellent. Major advantages are the fast response and good overall safety. Constitutional symptoms often disappear rapidly, which may contribute substantially to the gain in quality of life. Efficacy and safety are maintained even in long-term use. Because of certain risks and high costs TNF-blocking agents should be reserved for patients who respond poorly to conventional DMARDs or do not tolerate them.