AIM: To examine trends in neonatal, infant and under-five mortality rates in a northern Vietnamese district during 1970-2000, and to analyze socioeconomic differences in child survival over time. METHODS: Retrospective interviews with all women aged 15-54 years in Bavi district in Northern Vietnam (n = 14 329) were conducted. Of these women, 13 943 had been pregnant, giving birth to 26 796 children during 1970-2000. RESULTS: There was a dramatic reduction in infant and under-five mortality rate (47%) over time. However, the neonatal mortality rate (NMR) showed a very small reduction, thus causing its proportion of the total child mortality to increase. Mortality trends followed the political and socioeconomic development of Vietnam over war, peace and periods of reforms. There were no differences in under-five and neonatal mortalities associated with family economy, while differentials related to mothers' education and ethnicity were increasing. CONCLUSION: Interventions to reduce child mortality should be focused on improving neonatal care. In settings with a rapid economic growth and consequent social change, like in Vietnam, it is important that such interventions are targeted at vulnerable groups, in this case, families with low level of education and belonging to ethnic minorities.