The aim of this work was to test the histological criteria for assessing changes in joints and to conduct a comparative analysis of two experimental models of chronic arthritis in the rat. The basis was taken method of assessment of cartilage by Malkin, which was originally developed in the 1950s to describe the cartilage in osteoarthritis is not inflammatory arthritis. It has been shown that the administration of complete Freund's adjuvant simulates the condition of rheumatoid arthritis with a significant increase in pannus, marked degenerative changes in cartilaginous tissue, osteolysis, fibrotic ankylosis of the joints and led to the spread of the pathological process to the joints removed from the place of CFA injection. In contrast, administration of carrageenan contributes to development of chronic inflammatory arthritis, lacking immunological component with inflammatory of the periarticular space and a slight damage to the cartilaginous tissue of the joints, only near the injection site of carrageenan. These observations should be considered in preclinical studies the specific pharmacological activity of innovative drugs with antirheumatoid, anti-inflammatory and/or immunomodulating properties.