Hepatitis A virus (HAV) is transmitted mostly through exposure to contaminated food or water, or through exposure to infected persons. This infection can occur sporadically or in an epidemic form, confers lifelong immunity and it is preventable by a safe and effective vaccine. Therefore, prevention strategies are crucial and could eradicate the infection if they were successfully employed. In this chapter, authors summarize mode of transmission and preventive measures for HAV among the following population groups: travellers, health care workers, men who have sex with men, individuals who use illicit drugs, sewage workers, food handlers, military personnel, prisoners, blood transfusions recipients, haemophiliacs and patients with HIV and ch...