In the study, synovial fluid samples obtained from clinically healthy calves (control) and diarrheic calves with arthritis were examined by electrophoresis (SDS-PAGE) to determine the distribution of denatured proteins for understanding their clinical importance. In the study, 3-29 days old 7 healthy calves (control) and 19 diarrheaic calves observed in arthritis (2-75 days old) were used as material. Synovial fluid proteins were separated by SDS-PAGE (7.5% + 10% SDS-containing acrylamide, on 8x10 cm mini-gel) according to the molecular weights. Protein bands with the molecular weight of 48-50 kDa and 56-57 kDa were the main bands after SDS-PAGE analysis of joint fluids of calves with and without arthritis. Eighteen protein bands were dominantly found in arthritic group. As a result, joint fluid protein bands with the molecular weights of 205.5; 200-190; 144-140; 110-100; 64-62; 40-39 and <10 kDa may be important together or individually to determine the degree of severity of arthritis in calves. Moreover, these changes in protein bands may also be useful to understand the ethiologic factors in the pathophysiology of arthritis. Therefore, obtained results may have a diagnostic and prognostic value in the veterinary clinics.