CASEOUS lymphadenitis (CLA) caused by Corynebacterium pseudotuberculosis has been present within the UK for more than 10 years. In this relatively short period of time, the infection has spread from a single group of imported animals to become increasingly prevalent within terminal sire sheep flocks throughout the country. The disease now threatens to spread from these elite flocks into the rest of the commercial sheep industry. The condition responds very poorly to antibiotic treatment and, in the absence of a licensed vaccine, control must be based on careful examination of sheep and goats and appropriate management strategies. This article outlines the current status of CLA in the UK and discusses how it might be managed to prevent further spread.