Urolithiasis is not at present an important problem for the livestock industry in the United Kingdom, but the probable introduction of more intensive systems of management may change this position. The rapid fattening of male animals with high-energy diets predisposes to formation of phosphatic calculi and obstructive urolithiasis in the feed lot system of the USA and it is a form of this type of management which is most likely to be introduced to this country. For this reason, this review will be limited to the problem of phosphatic calculus formation, although other calculi, especially siliceous forms cause economic loss in extensive areas of the world.