Cystic hydatid disease, caused by Echinococcus granulosus, is a zoonotic disease principally transmitted between dogs and domestic livestock, particularly sheep. Humans are infected when they ingest tapeworm eggs, with disease occurring in most parts of the world where sheep are raised and dogs are used to herd livestock. The most common clinical manifestations are cysts in the liver (typically presenting with hepatomegaly) and/or lung (presenting with cough, haemoptysis, and dyspnoea). Diagnosis is usually made on the basis of serological tests in combination with imaging techniques. Treatment options include surgery, chemotherapy with anthelminthic agents, or—for liver cysts—PAIR (puncture–aspiration–injection–reaspiration). Echinococcosis is a major public health problem in several countries. Control programmes have been aimed at educating dog owners to prevent their animals from having access to infected offal. Vaccines against sheep hydatidosis and the dog tapeworm stage are promising alternatives.