Echinococcosis is a zoonosis caused by a tapeworm of the genus Echinococcus. Present worldwide, it is considered to be a re-emerging infectious disease because of a steep rise in incidence in various parts of the world. In Slovenia, it is prevalent mostly in the eastern part of the country. The infection can be asymptomatic for a long period of time. Cystic hydatidosis is caused by Echinococcus granulosus, while the alveolar form that mimics malignancy, is caused by E. alveolaris. The liver and lungs are the most commonly affected organs, but the disease can also cause a strong anaphylactic reaction. Abdominal ultrasound has a central role in diagnostics and is frequently combined with microbiological techniques. Current treatment is based on percutaneous approach, as only complicated cases are treated surgically. Albendazole is an effective antihelmintic drug that can be used as sole treatment or as adjuvant therapy.