BACKGROUND Cash transfers (CTs) are increasingly used as a strategy to alleviate poverty and improve child health outcomes in low- and middle-income countries. The Child Support Grant (CSG) is the largest CT programme in South Africa, and on the continent, targeting poor children from birth until the age of 18 with a monthly sum of R300 (USD30). Evidence on the CSG shows that early receipt of the grant is associated with improved child health outcomes. Since its implementation, one of the major concerns about the grant has been take-up rates, particularly for younger children. This paper reports results on take-up rates for 12-week-old infants residing in an urban township in South Africa. METHODS This is a descriptive study utilising data from a community-based, cluster-randomised trial which evaluated a programme providing pregnancy and post-natal home visits by community health workers to 3,494 mothers in Umlazi township, South Africa. RESULTS At the 12-week visit, half (52%) of the mothers who had enrolled in the study had applied for the CSG on behalf of their children, while 85% of the mothers who had not applied were still planning to apply. Only 38% (1,327) of all children had received the CSG. CONCLUSIONS In this study, many mothers had not applied for the CSG in the first few months after delivery, and only a third of children had accessed the grant. Further research is needed to understand what the current barriers are that prevent mothers from applying for this important form of social protection in the early months after delivery.