Animal models of arthritis are used to study pathogenesis of disease and to evaluate potential anti-arthritic drugs for clinical use. Therefore morphological similarities to human disease and capacity of the model to predict efficacy in humans are important criteria in model selection. Animal models of rheumatoid arthritis (RA) with a proven track record of predictability for efficacy in humans include: rat adjuvant arthritis, rat type II collagen arthritis, mouse type II collagen arthritis and antigen-induced arthritis in several species. Agents currently in clinical use (or trials) that are active in these models include: corticosteroids, methotrexate, nonsteroidal anti-inflammatory drugs, cyclosporin A, leflunomide interleukin-1 receptor antagonist (IL-1ra) and soluble TNF receptors. For some of these agents, the models also predict that toxicities seen at higher doses for prolonged dosing periods would preclude dosing in humans at levels that might provide disease modifying effects. Data, conduct and features of the various models of these commonly utilized models of RA as well as some transgenic mouse models and less commonly utilized rodent models will be discussed with emphasis on their similarities to human disease.