Abstract
A male German Shepherd dog, $2{\frac{1}{2}}$years of age, was admitted with sudden anemia, weakness, hyperpyrexia, anorexia and lethargy. The patient showed hypoplastic anemia, thrombocytopenia, absolute and relative lymphocytosis, absolute and relative granulocytopenia, hypoalbuminemia, slight hepatic disorder, slight azotemia, hematuria and proteinuria by the screening examination. The bone marrow aspiration smear showed high cellularity, severs infiltration of lymphoblasts and prolymphocytes, and mitotic figures of lymphoid cells. The liver aspiration smear demonstrated infiltration of lymphoblasts. Acute lymphoblastic leukemia was diagnosed as none of the superficial lymph nodes showed enlargement and marked functional disorder of important organs other than the liver was not found. The patient was treated with vincristine, cyclophophamide, predniosolone for chemotherapy and blood transfusion and either ampicillin or cefoperazone for supportive treatment. But the patient did not show marked remission and died 9 days after the start of the chemptherapy. The necropsy was not permitted.