Osteosarcoma (OSA) is the most common type of bone tumors in dogs, which has high metastasis ability. 80 % of dogs with OSA die due to lung metastasis. As a result its treatment is a challenge for veterinary practitioners. The authors discuss the etiology, pathogenesis and the possible risk factors of OSA. The article focuses on literature review and the study of recent advances in OSA treatment. The authors describe therapies which have significantly prolonged the lives of dogs, as well as those that have proven to be ineffective. Advantages and disadvantages of limb amputation and limb-sparing surgery have been described. Authors present also the results of both single agent's therapies with the most commonly used drugs as cisplatin, carboplatin and doxorubicin and compare them to the results obtained using combined chemotherapy. The use of nanotechnology as a new approach in OSA treatment in order to avoid multidrug resistance and reduce negative side effects of cytostatic drugs is presented. The main reasons of the therapies failure are also provided in this article.