Abstract: This study investigated the changes in the haematological and haematochemical parameters in osteoarthritis secondary to experimental Medial Patellar Luxation (MPL) along with single grove damage to the femoral condyles in the dog. MPL was surgically produced in the left stifle joint in 20 skeletally mature mixed small breed dogs (age 2 to 6 years, weight 2.8 to 9 kg) by placing purse string sutures around the parapatellar fibrocartilage and anchoring the patella with the fabellar ligament and by medial imbrication and lateral release. Physical and radiographic examinations of the experimental stifles were performed at every 1.5 months intervals to evaluate the position of the patella and development of osteoarthritis. The blood samples were collected prior to and 3, 6 and 9 months after the experimental induction of MPL and were subjected to Complete Blood Count (CBC) and Chemistry Screening (CS). In the CBC parameters, a significant difference in the platelet count (PLT) and in the CS parameters, a significant difference in the values of Alkaline Phosphatase (AP) were observed. The changes in the CBC and CS parameters can be impressive but cannot be the sole determinants of osteoarthritis in dogs.