Introduction: A case report of a DSH breed cat suffering from acute lymphoblastic leukemia. Materials & Methods:The present study on a 9-year-old, female, sterilized DSH cat. A cat refferd to the veterinary hospital with clinical signs of weight loss on 18 September 2022. A physical examination was performed by a small animal internal medicine specialist and blood tests including CBC and biochemical factors were subsequently taken from the present case. Results:According to the results of the blood test and clinical symptoms, according to the leukocytes and their morphology, therefore ALL disease was diagnosed in this cat collar. Leukomoid reaction, lymphocytosis, and the presence of neoplastic lymphocytes in the blood circulation have been reported in the blood smear of this patient. Conclusion:In this study, the most obvious clinical sign of cat was weighting loss despite a good appetite. Our findings following the physical examination of the patient included: fever above 40 °C, dehydration. Examination of this patient revealed no swelling of the lymph nodes or pain in the abdominal area. The presence of large and neoplastic lymphocytes in the blood circulation confirmed by the examination of CBC and blood smear of the case, also leukomoid reaction was also reported.