Background: Microtia is a congenital defect characterized by disturbances in the size and form of the ear lobe. Anotia corresponds to the absence of the ear lobe. Aim: To study the prevalence of microtia and anotia at the Maternity of the University of Chile Clinical Hospital. Material and methods. Analysis of the database of the Latin American Collaborative Study of Congenital Defects (ECLAMC). All newborns and stillborns with congenital defects are incorporated to this database. Results. The prevalence of microtia-anotia in the period 1982-2001 was 8.7 per 10,000 born alive. Chilean hospitals have an uniform prevalence of 5.2 per 10,000 born alive. Thirty seven percent presented as isolated malformations and the rest were associated to other defects. Eighty six percent of non isolated cases were pan of a syndrome. Sixty eight percent were mild or moderate firms and the rest, severe forms. Two cases were stillborns and two newborns died before hospital discharge. Conclusions:. The prevalence of microtia in this hospital and in the rest of Chilean hospitals is significantly higher than in the rest of non Chilean hospitals participating in the ECLAMC, that is 4.1 per 10,000 born alive.