Stockyards are premises where livestock from different sources are brought together for a period of time, before returning to their place of origin, or moving on to new premises or to the abattoir Such premises pose particular problems for disease control, as they are potential sources for the dissemination of disease agents over wide geographical areas. The author describes a thorough programme of cleaning and disinfection for use during the routine operation of a stockyard. A differ ent programme is described for use in the event of an outbreak of an Office International des Epizooties List A disease, taking into account the extra risks involved in such a disease outbreak.