Changes in infant mortality in Réunion since the end of the Second World War have been among the most rapid in the world. Whereas the infant mortality rate was over 165 per 1,000 births fifty years ago, it is currently under 10‰. All the components of infant mortality have contributed to this reduction even though each has evolved at its own pace. This evolution has been accompanied by substantial changes in the structure by cause of death, with a sharp decline in infectious and respiratory diseases and a growing proportion of deaths from perinatal disorders and congenital anomalies. Generalized access to health care and the medicalization of pregnancies and childbirth have undoubtedly contributed to reducing infant mortality, but changes in reproductive behaviour and other socio-economic factors have also contributed to the progress observed. Concerns remain, however, regarding children born in the most deprived socio-economic categories.