ABSTRACT. Monger S.G.B., Pereira W.L.A, Pituco E.M., Nogueira A.H.C., Lima M.S., Viana R.B. & Barbosa N.G.S. [Lymphosarcoma in female buffaloe - Case report.] Linfossarcoma em uma búfala - Relato de caso. Revista Brasileira de Medicina Veterinária, 38(1):19-24, 2016. Programa de Pós-Graduação em Saúde e Produção Animal na Amazônia, Universidade Federal Rural da Amazônia, Avenida Presidente Tancredo Neves, 2501, Bairro Montese, Belém, PA 66077-830, Brasil. E-mail: firstname.lastname@example.org Lymphosarcoma is a lymphoid tumor that arises more frequently in solid hematopoietic organs. This study aimed to describe pathological aspects of a case of lymphosarcoma in the buffalo species. A buffalo, female, six years old from a buffalo unit located in the metropolitan area of Belém came to death. The necroscopic exam was undertaken and altered tissue fragments were collected for histological procedure and nested PCR for research of bovine leukemia virus (BLV). Additionally, it was performed a serologic evaluation from the immunodiffusion Agar gel of 35 buffalo herd in the study. Clinicaly, the buffalo had included depression, anorexia and prolonged recumbency. During the necropsy there were multiple nodular lesions with generalized lymphadenopathy whitish nodules as well as in kidney and heart. In the histopathologic exam were observed atypical lymphocytic cells in the lymph nodes, bordering tubules and glomerulus, in the mesenteric fat and in some follicular spleen center. In this study, samples of lymph nodes and kidneys with nodules underwent nested RT-PCR were negative and none of the herd were positive to the immunodiffusion test Agar gel for leucose virus (0/35). From the results, it can be suggested that the buffalo tumor showed sporadic form, in this case there was no relationship with the BLV.