Osteosarcoma (OSA) is the most common bone tumor of canines comprising up to 90% of all cases. Large and giant breeds are overrepresented with an average age of diagnosis of 7 years old. The disease is highly metastatic and carries a guarded to poor prognosis. Diagnosis is often presumptive and based on clinical presentation and radiographic evidence of the lesion in question, but histopathology remains the only way to definitively diagnose this disease. Amputation with adjuvant chemotherapy has been the Gold Standard treatment, but recent advances in medicine have seen the success of limb sparing procedures as well as definitive radiation therapy. Palliative therapies have also advanced significantly and include new drugs like Pamidronate, as well as traditional treatments like palliative radiation therapy. Treatment plans are based on the stage of the disease, and diagnostic tools are becoming more sensitive, such as computed tomography. This case will be used to demonstrate the diagnostic process, treatment options, and advancements in managing and treating this disease.