Chile has attained the second lowest Infant Mortality Rate (IMR) in Latin America, behind Cuba. However, the question remains, is this attainment shared by all Chileans? Chile is recurrently ranked as one of the most unequal countries in the OECD. Our study focuses on the administrative information of the territory (divided into approximately 350 districts or "communes"), in order to estimate the impact of the residential socioeconomic level on the IMR. The findings confirm the relationship between socioeconomic level and IMR in the communes of Chile during the 1990-1999 period. They also show that it continuously declines until it virtually disappears by 2010. On average, the lowest socioeconomic level communes have managed in recent years to counter a range of disadvantages in IMR-affecting variables. Noteworthy among these is the lower schooling-level of this population group.