Breastfeeding is the major strategy for prevention of morbidity and mortality resulting from diarrhea in the first few years of life. Health-system and community based interventions have been shown to increase the prevalence of breastfeeding and reduce the incidence of diarrhea and associated healthcare costs in infancy. The protective effect of breastfeeding is attributable to a complex of acquired and innate factors unique to human milk that have anti-infective, anti-inflammatory, and immunoregulatory functions, including secretory antibodies, oligosaccharides, glycoconjugates, lactoferrin, leukocytes, cytokines, and other agents. The American Academy of Pediatrics recommends exclusive breastfeeding until the infant is approximately 6 months of age, with timely introduction of complementary foods and continued breastfeeding to a year, or longer if desired. The number of deaths of children that could be prevented worldwide each year if these breastfeeding recommendations were followed has been estimated to be more than 1 million.