Hepatitis E is an important public health disease in developing countries where sanitary conditions are not well established. In developed countries, it is sporadic and mainly "imported". The causative agent of hepatitis E, hepatitis E virus (HEV), is a single-stranded positive-sense RNA virus, that belongs to the genus Hepevirus in the family Hepeviridae. Recent development of specific HEV RNA and HEV antibody detection revealed cases of indigenous HEV infection. Many cases are associated with uptake of raw meat of HEV-infected animals. Although the natural life cycle of HEV is not known, new aspects of HEV infection, zoonosis, is emerged.