Eight calves with sporadic bovine leukosis are described. The common features were generalized lymphadenopathy, visceral involvement and raised total leukocyte and lymphocyte counts. Agar gel immunodiffusion tests for bovine leukemia virus antibodies were negative in eight animals and in all animals from three herds of origin. Lymphocytic nuclear pockets were found in the tissues of one calf but attempts to isolate bovine leukemia virus from two animals were unsuccessful.