Nevirapine resistance has been detected in a considerable proportion of women after single-dose nevirapine (SD-NVP) for the prevention of mother-to-child human immunodeficiency virus-1 transmission. As a result, concern has been raised about the effectiveness of subsequent nevirapine-based treatment. Studies in Thailand, Botswana, and South Africa have assessed virologic treatment response after SD-NVP. These studies did not find any significant difference in virologic response for women who began treatment >6 months after SD-NVP exposure. Two studies found worse response rates in women when treatment was initiated within 6 months of SD-NVP exposure. Furthermore, 2 studies found no difference in human immunodeficiency virus transmission rates from mother to child after the receipt of SD-NVP in repeat pregnancies. These data support the use of SD-NVP as 1 option for the prevention of mother-to-child human immunodeficiency virus-1 transmission in resource-limited settings, particularly in settings where more complex regimens are not yet available. Further research in the optimization of perinatal prevention regimens is needed.