Thirteen cattle which were suffering from infection with bovine leukemia virus or persistent lymphocytosis, showing very slight or hardly detectable lesions were subjected to pathologic examination for initial lesions of enzootic bovine leukosis. Careful macroscopic observation revealed lesions swollen up and whitish in color on the cut surface of some of the lymph nodes. These lesions were confirmed by histolgic examination as those of marked follicular hyperplasia accompanied with atypical blastic cells in the sinuses and paracortical area of the lymph nodes. Peyer's patches were extended and thickened due to follicular hyperplasia in the lymphatic tissue. Whitish spotted lesions on the gastric mucosa were also noted. Accumulation of atypical cells was noted microscopically in the upper layer of the propria of the stomach. From the findings obtained, it was stressed that the leukotic lesions initiated mainly in the lymph nodes. The significance of occasional infiltration of macrophages, as well as eosinophils, in the initial lesions was discussed.