SINCE Anitschkow and Chalatow1 in 1913 first induced lesions simulating human atherosclerosis in rabbits by feeding a diet rich in cholesterol, many workers have used rodents for this purpose despite the fact that spontaneous atheroma, apart from microscopic lesions, rarely develops in these mammals. Experimental atheroma has been produced by various dietetic alterations in other animals, including monkeys2,3, pigs4, chickens5,6 and geese7, but the parrot family (Psittacidae) have rarely been used although the more aged, captive birds in this order develop spontaneous atheromatous-like arterial lesions of an intensity usually seen only in man8,9. This communication describes cholesterol atheromatosis induced in budgerigars (Melopsittacus undulatus), which are the least expensive and most easily reared and housed of the psittacines.