Detection of bovine leukemia virus antigens can induces humoral immunity in cow were evaluated. Fifteen lymph node from infected cows that had positive results in AGID and ELISA tests for BLV and have clinical signs of lymphosarcoma, in addition five lymph node from apparently healthy cows that had negative results in serological tests. After preparation of extract of lymph nodes, all of the samples electerophoresed in SDS-PAGE system in discontinuous 5 and 10% gel. All gels transferred to nitrocellulose membrane in Biorad blotting system. Antigens were detected by BLV positive antisera by using HRPO conjugated protein G and Tetramethyl benzidine as substrate. At least 25 proteinal band were detected in SDS-PAGE of tumoral and normal lymph node. In tumural tissues two additional band 24 and 51 kda were detected. In western blotting of those samples, gp51 antigen were detected in all tumoral lymph nodes , p24 antigen were detected in 5 samples from 15 samples and in non of apparently healthy samples non of those two antigens did not detect in WB test. These results were shown that gp51 were expressed in high level in tumors and induced a strong humoral immune response but p24 is a weak and non-common antigen in lymphatic tumors. Gp51 is most important and first antigen in all of the cases that infected by BLV.