During the last decade there has been increasing interest in possible long-term benefits of breastfeeding for health and development. Most relevant studies published from the second half of 2001 to 2006 suggest that breastfeeding is likely to protect against later obesity, type 1 diabetes, coeliac disease, inflammatory bowel diseases and childhood cancer. Also, breastfeeding seems to have beneficial effects on later cardiovascular risk factors. A positive association between breastfeeding and cognitive development continues to be the most consistent and important effect, whereas the effect of breastfeeding in the prevention of atopy remains controversial. Possible mechanisms which might mediate the protective effect of breastfeeding are considered. Evidence suggests that breastfeeding can to some degree programme future health, although most studies are observational and cannot prove causation. Promotion of breastfeeding is of great importance and may contribute to the prevention of some major health risks at the population level.