Experimental septic arthritis was induced in the radiocarpal joint of 18 donkeys by intra-articular injection of Staphylococcus aureus (3-4X106 CFU). The inoculated animals were divided into three groups (6 donkeys in each group). The arthroscopic examination was carried out before induction of septic carpitis and 3 days (group I), 14 days (group II), and 28 days (group III) after induction of infection. The arthroscopic examination of group I revealed hyperemia of synovial membrane and hypertrophied villi. In group II, severe hyperemia of synovial membrane, hypertrophied villi, pannus in the joint cavity and beginning of articular cartilage erosion were found. In group III, severe hyperemia of synovial membrane, hypertrophied villi and more prominent articular cartilage erosion were present.