Hydatid disease of the liver is caused by the tapeworm Echinococcus granulosus, and the highest incidence of human infestation occurs in sheep and cattle-raising areas. Although, still an uncommon occurrence, it is being seen with increasing frequency; hence, it is important that surgeons make themselves aware of the pathology and treatment of the disease. The liver is most commonly involved, although many other organs, including lungs and brain may also be affected. An echinococcal cyst of the liver was reported in a patient who is a resident in Northern Ireland but had originally lived and worked in mainland Britain. Details of the lifecycle, pathology, diagnostic techniques and surgical management of hydatid cysts are reviewed.