The criteria for selecting and establishing a animal model for arthritis were described. Rats are the most frequently used animals. Adjuvant and Myocobacterium induced arthritis provide a model of chronic joint inflammation, although significant differences exist when compared with human disease. A better model of arthritis in rats and mice can be induced by the injection of one strain of Mycoplasma arthritidis. An even better model is presented by rabbits first immunized against a protein such as heterologous fibrin or albumin, and then challenged by the same protein injected directly into a joint. This results in a localized chronic arthritis pathologically similar to that of man. Arithritis can also be induced in rabbits by the injection of polymers such as chitinor or Concanavalin A into the joint. Although there is no lack of arthritis animal models, there is no animal model which gives a true replication of rheumatoid arthritis.