Eugenics was defined by Galton as ‘the science which deals with all influences that improve the inborn qualities of a race’. In Peru, eugenics was related to social medicine and mental hygiene, in accordance with the neo-Lamarckian orientation, that predominated in Latin America. Peruvian eugenists assumed the mission of fighting hereditary and infectious diseases, malnutrition, alcoholism, drug addiction, prostitution, criminality and everything that threatened the future of the ‘Peruvian race’. There were some enthusiastic advocates of ‘hard’ eugenic measures, such as forced sterilization and eugenic abortion, but these were never officially implemented in Peru (except for the compulsory sterilization campaign during the 1995–2000 period). Eugenics dominated scientific discourse during the first half of the twentieth century, but eugenic discourse did not disappear completely until the 1970s.