The advances in the understanding of the pathogenesis of the autoimmune diseases have led to new treatment targets. Biological agents enhance or replace conventional immunosuppressive therapies in the treatment of autoimmune diseases. TNF-α has been validated as a good treatment target but the potential modalities also include the inhibition of the interaction between LFA-3 (lymphocyte function-associated antigen 3) and CD2, the blockade of the IL-1 receptors, the antibodies against the α4 integrins, the antibodies against B-cell CD20 and the inhibition of the activation of T-cells. The new treatments have had a major impact on inflammatory symptoms, the radiological damage and the anemia of chronic disease in rheumatoid arthritis and have substantially controlled the signs and symptoms in the spondylarthropathies group and plaque-type psoriasis. The efficacy of the biologic agents in systemic lupus erythematosus warrants further investigation but there have been some promising results in proliferative lupus nephritis. Several small studies have explored their use in the treatment of Sjogrens syndrome, adult onset Stills disease and several vasculitides but the results are still preliminary and warrant confirmation. The efficacy of the biological agents has been impressive. Susceptibility to infections has always been a major concern; a high level of suspicion is necessary and strategies should be implemented for the prevention, the rapid identification and pre-emptive therapy of such infections.