We evaluated growth indices in two cohorts of Malawian infants exposed to tenofovir, lamivudine and efavirenz in utero and during 12 months of breastfeeding, and to stavudine/zidovudine, lamivudine and nevirapine in utero and during 6 months of breastfeeding. Growth indices were similar in the two cohorts at one and 6 months but were significantly better in the first group at 12 months, suggesting no negative effect of tenofovir and a significant benefit of extended breastfeeding.