In India, HIV prevalence among pregnant women is reported to be 0.3 per cent (1). HIV transmission from mother to child can occur in utero, intrapartum (during labour) or postpartum (through breastfeeding). In the absence of any interventions, about 25-30 per cent of infants will be infected with HIV. Several regimens have been tested for prevention of parent-to-child transmission (PPTCT), including nevirapine (NVP) given as a single dose to the mother at the time of delivery followed by a single dose to the infant within 72 h (Sd-NVP) (2). Resistance to nevirapine has been described after use of single drug preventive treatment, which is why triple drug therapy is recommended as the preferred option for treatment (3,4). While the prevalence of resistance mutations decreases with time after exposure to Sd-NVP, there is some evidence that women with pre-existing mutations as well as those exposed to Sd-NVP but without mutations respond less well to antiretroviral treatment (5). Emergence of antiviral drug resistant mutations (DRM) among Indian women who had received Sd-NVP regimen for PPTCT is not described. Our aim was to study the presence and pattern of drug resistance (DR) at baseline and after delivery among antenatal women exposed to Sd-NVP and determine the HIV status of their infants.