A 4-year-old neutered male Scottish Terrier, weighing 10.4 kg, presented with hematuria for the past 10 days. Ultrasonography revealed multiple masses in the apex and trigone of the bladder. A catheter biopsy was performed, and the histopathological diagnosis was non-invasive urothelial carcinoma (transitional cell carcinoma) with low to medium grade pathological malignancy. Treatments with piroxicam alone, vinblastine and firocoxib, toceranib and firocoxib, and firocoxib alone resulted in a partial response or stable disease. The patient showed no regional lymph node metastasis or distant metastases, maintained stable disease, and had an excellent quality of life at 1681 days after the start of treatment.