This study analyzes temporal trends in infant, neonatal and postneonatal mortality rates in Argentine in two periods (1995 to 1997, and 2003 to 2005) and the association with a poverty index. A poverty index was associated with infant, neonatal and postneonatal mortality rates of each department of the country. Birth and infant mortality data by department, published by Ministerio de Salud de la Nación, were used. As socioeconomic level of each area was used an index of Unsatisfied Basic Needs (NBI), according to 2001 National Census. Five clusters (quintiles) were organized according to socioeconomic level. We estimated the Relative Risk for infant, neonatal and postneonatal mortality. Even if infant, neonatal and postneonatal mortality rates decreased between both periods of study (1995-1997, and 2003-2005), risk of infant death remained higher for clusters with higher NBI incidence. Neonatal mortality risk between both periods keeps in high level for clusters with greater incidence of poverty. Post neonatal mortality risk between both periods and for the same clusters had decreased, but his level was high. It must take into consideration that inside these variations the risk is high and evidences the persistence between both periods of inequality and higher risk for the clusters with higher incidence of poverty. In the framework of infant mortality (and its components) decrease in Argentine, socioeconomic inequality in infant death persists between both study periods.