In this study, Bovino Leucosis (BL) infection in five-years old Holsteln breed cow was investigated clinicaly. hematological and serologicaly. Clinical examinations revealed weakness, lymph nodes enlargements in neck and plica genus and weak exophtalmus in eye. Hematological^, it was determined to increase total leucocytes counts. Serologically, BLV aniibodies were detected in blood and milk serum samples by Agar-Gel Immunodiffusion (AGID) and Enzyme Linked Immunosorbent Assay (ELİSA).