Visual potentials induced with a checker pattern were studied in a group of patients with damage to the visual pathways at different levels, and were compared with similar potentials in 10 adult subjects without diseases. A statistically significant prolongation of latency of the main deflections (N1, P max and N2) was observed in the group of 14 patients with optic nerve damage, while in 10 patients with lesions above the chiasma different, often normal responses were obtained. High-grade deformity of visual potentials was observed in 2 cases of visual agnosia. The study of visual evoked potentials may be in the opinion of the authors, useful in cases of damage to the optic nerve, retina and cortical visual centres.