Migrations are a worldwide phenomenon, where in South América Chile has become a receiving country of immigrants. The arrival of foreigners to the country, besides being a necessity due to local demographic changes with tendency of investment of the population pyramid, it can cause local epidemiological changes, presenting unknown diseases and increasing others controlled by monitorization epidemiological programs. In Chile, 1.3% of the population are foreigners, mainly becoming from countries like Perú, Argentina, Bolivia, Ecuador, Colombia and recently Palestine. 11.8% of immigrants are younger than 14 years-old, where 40% of them are not enrolled in the Public Health System and 30% do not have identification card. A period of latency of 6 months is estimated since the illegal entry to the country until it is incorporated to the National Health System. General doctors and pediatricians must be prepare for rare diseases in the country.