Disposal records from nine herds and pertaining to 4,960 animals whose ages ranged from 2½ to 18 years were used to investigate the effect of sunlight on “cancer eye”. The age-adjusted incidence increased significantly with: (1) increase in average annual hours of sunshine; (2) decrease in average latitude; and (3) increase in average altitude. These criteria were thought to reflect differences in the ultraviolet component of sunlight. Other evidence of an association between sunlight and cancer in the bovine, man and laboratory animals was also mentioned.