Infant mortality and its neonatal and postneonatal aspects are important health indicators and thus warrant regular analysis even in developed countries where the rates thereof have dropped considerably. This study is aimed at describing the changes recorded in these rates in Andalusia over the past twenty-five years. The annual infant, early and late neonatal and postneonatal mortality rates have been calculated for the 1975-1998 period. Poisson regression was used to estimate the annual percentages of change in the rates for the 1975-1986 and 1987-1998 periods, as well as for the entire 1975-1998 period. An analysis was also made of the proportional mortality rate due to infectious, respiratory, congenital causes, disorders having arisen during the perinatal period and all other causes, as well as the ratio for mortality rates due to disorders having arisen in the perinatal period and for all causes as a whole for the 1994-1998 four-year period as compared to the 1975-1979 period, in infant, neonatal (early and late) and postnatal periods. The greatest percentage drops were in early (6.38%) and late (4.6%) neonatal mortality. The ratio for mortality rates due to disorders having arisen in the perinatal period for the 1994-1998 and 1975-1975 periods is 10 for the postneonatal mortality rate, whilst it is under 1 for the late (0.63) and early (0.33) neonatal and infant (0.30) mortality. Mortality during the infant, early and late neonatal and postneonatal periods dropped sharply during the 1975-1998 period. The risk of death due to disorders arising during the perinatal period among children ranging from four weeks to one year of age (postneonatal period) rose tenfold during the 1975-1979 and 1994-1998 periods.