This is a case of a geriatric, male-castrated dog with epitheliotrophic, T-cell lymphoma of the bladder and suspected metastasis to the liver. The histologic and ultrasonographic features of the disease are described. The dog was treated with the L-CHOP chemotherapy protocol and progress followed for several months. A partial response was achieved, and the dog's quality of life was greatly improved. Very little information specific to lymphoma involving the bladder is known, particularly regarding response to treatment. This report emphasizes the need to histologically identify an imaged bladder mass, as appropriate treatment depends on the diagnosis.