OBJECTIVE: Viral resistance occurs with high frequency after single-dose nevirapine. We aimed to evaluate the safety and resistance profiles of a combination of tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) in HIV-1-infected pregnant women and their newborns. DESIGN: An open-label phase I/II trial in Côte d'Ivoire, Cambodia and South Africa. METHODS: Women received antenatal zidovudine, intrapartum single-dose nevirapine and two tablets of TDF/FTC and one daily tablet of TDF/FTC during the 7 days postpartum. Their infants received single-dose nevirapine and zidovudine for 1 week. Serious adverse events (SAEs), kinetic of maternal plasma HIV-1 RNA viral load, genotypic resistance at 28 days postpartum and paediatric HIV-1 infection at 3, 28 and 45 days of life were assessed. RESULTS: Thirty-eight HIV-1-infected pregnant women were enrolled (19 in Abidjan, 12 in Phnom Penh and seven in Soweto) with a median CD4 cell count of 450 cells/microl and median viral load of 4.08 log10 copies/ml. Women received TDF/FTC 4.9 h in median before delivery. Biological SAEs occurred in nine women. Among 39 live births, nine infants had clinical SAEs, including four deaths, and two developed severe anaemia. These SAEs were not likely to be related to TDF/FTC. Maternal viral load decreased by a median of 0.90 log10 copies/ml at 2 days postpartum and returned to baseline value at 28 days. No intrapartum HIV transmission was reported. No genotypic resistance mutation to zidovudine, nevirapine, FTC or TDF was detected. CONCLUSION: The TDF/FTC combination was well tolerated in delivering women and exposed newborns. Nevirapine viral resistance appears to have been avoided by the intrapartum and 7-day postpartum TDF/FTC regimen.