Hepatitis E virus (HEV) is mainly transmitted by the fecal-oral route via contaminated water. HEV is considered as endemic in many countries of tropical and subtropical region such as Asia, Africa and Mexico. In developed countries, HEV has been documented in patients who traveled to areas in endemic region. HEV infection is also a zoonotic disease and there are animal reservoirs for hepatitis E infection. Other risk factors for hepatitis E infection are working in pig farms, contact with domestic cats slaying mice, consuming uncooked liver pig or raw shellfish. Recent seroepidemiological studies revealed that anti-HEV antibodies are present in various animal species, such as pigs, rodents, deer, chikens, dogs, sheep and goats, both developing and industrialized countries. Phylogenetically, HEV has 4 major genotypes. This genotypes are genotype 1 (Asia and Africa), genotype 2 (Mexico, Nigeria, Chad), genotype 3 (USA, Italy, New Zealand, Greece, Spain, UK, Argentina, Austria) and genotype 4 (China, Taiwan).