Lymphoma is one of the most observed neoplasias in dog. It can be classified as alimentary, mediastinum, extranodal or multicentric, which is the most common form. This neoplasia appears not to have any sexual predisposition and the average age of occurrence is at seven years. Approximately 67% of the cases are derived from B-cell lymphocytes, which are generally more aggressive. Patients treated with polychemical therapy can have survival from six to nine months. There are some chemical therapeutic protocols, which are divided into phases of induction of remission, intensification, maintenance, and rescue. There are controversies as to the choice of rescue protocol to be followed; nonetheless here is a consensus between the authors as to which rarely a rescue therapy provides a remission of long duration. Among the existing rescue protocols, D-MAC (dexamethasone, melphalan, actinomycin D and cytosine arabinoside) is of a lower toxicity, with an 80% remission rate, and its use is recommended in six to eight cycles. However, it can be indicated to be used for an indeterminate period of time until the lymphoma recidivates once more. An eight year old, female, English Cocker Spaniel, showing a history of bilateral sub-mandibular lymphadenomegaly for one week, was treated at the Veterinarian Hospital, "Professor Ricardo Alexander Hippler" of the University Center of Vila Velha. Physical examination revealed generalized peripheral lymphadenomegaly, hepatomegaly, and splenomegaly. Upon conducting aspiratory cytology with a fine needle of the lymph nodes, the diagnosis was found to be of multicentric B-cell centroblastic lymphoma of the lymphocytes, polymorphic with a high degree of malignity, classified in the range of stage IV and as a sub-stage b in the worldwide system of the World Health Organization. Chemotherapy was initiated according to the protocol on remission induction of COAP (cyclophosphamide, vincristine, cytosine arabinoside and prednisone) for a six week period achieving total remission of the neoplasia. Following this stage, the protocol of LPM (chlorambucil, methotrexate and prednisone) maintenance was carried out; however after fifty days, the generalized lymphadenopathy returned, which characterized the recidivism of the lymphoma. As a consequence, the rescue protocol of D-MAC for 29 cycles was instituted. Following this period, the animal died after having convulsive crises. Both the duration of the survival time of this animal, which was that of 16 months, and the period of remission (29 cycles) of the neoplasia in the rescue protocol, had been superior to those found in available literature.