Despite the widely documented health advantages of breastfeeding over formula feeding, initiation rates remain relatively low in many high-income countries, particularly among women in lower income groups. The objective of this paper is to evaluate the effectiveness of interventions which aim to encourage women to breastfeed in terms of changes in the number of women who start to breastfeed. We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (July2007), hand searched the Journal of Human Lactation, Health Promotion International and Health Education Quarterly from inception to 15 August 2007, and scanned reference lists of all articles obtained. Selection criteria: Randomised controlled trials, with or without blinding, of any breastfeeding promotion intervention in any population group, except women and infants with a specific health problem. One review author independently extracted data and assessed trial quality, checked by a second author. We contacted investigators to obtain missing information. Main results: Eleven trials were included. Statistical analyses were conducted on data from eight trials (1553 women). Five studies (582 women) on low incomes in the USA with typically low breastfeeding rates showed breastfeeding education had a significant effect on increasing initiation rates compared to standard care (risk ratio (RR) 1.57, 95% confidence interval (CI) 1.15 to 2.15, P = 0.005). Subgroup analyses showed that one-to-one, needs-based, informal repeat education sessions and generic, formal antenatal education sessions are effective in terms of an increase in breastfeeding rates among women on low incomes regardless of ethnicity and feeding intention. Needs-based, informal peersupport in the antenatal and post-natal periods was also shown to be effective in one study conducted among Latina women who were considering breastfeeding in the USA (RR4.02, 95% CI 2.63 to 6.14, P < 0.00001).