Travelers' immunization has 2 aims: for the traveler, to prevent the risk of contracting an endemic disease during his stay abroad; for the community to prevent the risk of importing an infectious agent yet unknown in the country. Travelling offers an opportunity to update routine immunizations: tetanus, diphtheria, poliomyelitis, hepatitis B; for young people: measles and rubella; for elderly people: influenza. Two vaccinations are compulsory: yellow fever for travelers to tropical Africa and Amazonian forest; meningococcus A + C for Mecca pilgrims. Other vaccines are recommended for travelers to specific areas: typhoid fever, hepatitis A, cholera in countries with poor hygiene; rabies for exposed travelers (expatriates, trekkers...); Japanese encephalitis for persons spending a month or longer in rural agricultural areas during the monsoon season; tickborne encephalitis for persons visiting forested areas of central Europe from may to september. Yet, most of travelers' diseases such as malaria cannot be prevented by vaccination and appropriate preventive measures (chemoprophylaxis and protection against insects) should be taken.