ABSTRACTThis paper describes the chemotherapeutic response of 90 cases of canine multicentric lymphoma. All the dogs were treated with a combination protocol using cyclophosphamide, vincristine and prednisolone. Forty‐seven dogs received additional intravenous cytosine arabinoside on the first four days of treatment. Eighty‐eight per cent of all cases had shown either a complete or partial response to this treatment at six weeks from the start of treatment and the overall mean survival time was 37 weeks (SD = 35.8). There was no significant difference in response or survival rates between the two treatment groups. The age and sex of the patient, the clinical stage of the disease and previous treatment with corticosteroids were all analysed to determine whether these parameters were of prognostic significance. Those dogs in clinical stages 4 and 5 carried a worse prognosis than those in stages 1 to 3. Previous treatment with corticosteroids adversely affected both tumour response and patient survival ra