Thirty eight rams have been divided into two groups. One of them was infected with BLV and another served as the control. The presence of antibodies against BLV was assessed with the AGID test and ELISA at the intervals of one week. Besides, all the rams were assayed for the presence of antibodies against RT by means of the AGID test using as antigen the enzyme from the FLK culture. Antibodies against RT were found in four experimental animals. In two rams the antibodies against gp 51 antigen and RT were detected simultaneously. One animal with a constant presence of antibodies against RT died because of tumorous lesions. It seems to exist a correlation between the presence of antibodies against RT and the development of tumorous lesions in case of the disease. However, this hypothesis should be confirmed on a larger group of animals.