Radiographic examination of the distal radius and ulna of dogs showed changes in metaphyseal areas of both bones characteristic of hypertrophic osteodystrophy (HOD). The serum of the patients showed increased activity of alkaline phosphatase (ALKP) and elevated concentrations of Ca and P. Oral application of vitamin C and injection of sodium salt of hyaluronic acid in the bolus caused a reduction in swelling, disappearance of pain symptoms around the joints, and increased appetite. Radiographic examinations performed on the 60th d of treatment revealed the withdrawal of the changes characteristic for HOD. The chosen biochemical parameters tested during the treatment showed a decrease in comparison to the values before treatment, namely: ALKP by 27.7%, Ca by 22.2%, P by 12.3%, and Mg by 2.4%. Clinical condition of the animals was defined as good or very good. The use of hyaluronic acid and vitamin C in the treatment of HOD in the first stage of the disease proved to be highly successful, resulting in the inhibition of the disease course.