Background: Chile is receiving immigrant populations coming from other Latin- American countries. Aim: To determine the prevalence of Common Mental Disorders (CMD) among immigrants who live in Independencia, a quarter in Santiago, Chile. Material and Methods: A cross sectional study was carried out in the primary health care clinic and in the state-funded school of Independencia. A representative sample of 282 adults and 341 children were interviewed. Mental disorders were diagnosed using CIS-R and MINI structured interviews. Results: The interviewed immigrants came mostly from Peru. The prevalence of mental disorders in the adult population was 17.8% and among children, it was 29.3%. Conclusions: The adult immigrants have a lower prevalence of mental disorders than the Chilean population but it increases among children. Barriers of access to health services, that should be solved, were detected.