This study was carried out in order to serologically and haematologically determine the prevalance of Bovine Leukaemia Virus infection in cattle raised in Kars and environs. For this purpose a total of 443 blood samples and 383 milk samples belonging to the various breeds (Zavot, Holstein, Brown-Swiss and Native), and sexes (383 female, 60 male) were examined serologically (Agar Gel Immunodiffusion (ACID) and Enzyme Linked Immunosorbent Assay (ELISA)) and haematologically (lymphocyt counts, total leucocyt counts and haematocrit value). All of the 443 blood samples and 383 milk samples examined serologically by AGID and ELISA tests were found to be negative in EBL. As a result of the haematological examination of the blood samples taken from 443 cattle without coagulant. 402 were found to be within normal values, 28 to be obscure, and 13 to be positive. Since these findings were not supported by the serological data, the results were not considered as significant.