2022-02-232022-12-232022-02-232021-12-14https://ri.ucsal.br/handle/prefix/4771Introduction: Recent data from the literature prove the effectiveness of breastfeeding in reducing the risk of childhood leukemia, among these studies, a meta-analysis found that 14 to 19% of all cases of children with leukemia can be prevented through exclusive breastfeeding until 6 years of age. months. Therefore, the aim of this article is to assess the impact of breastfeeding on the prevention of childhood leukemia. Methodology: Narrative review, search for articles in the Medline databases (PubMed), the Scientific Electronic Library Online (SciELO), the Latin American and Caribbean Literature in Health Sciences (LILACS) and the Virtual Health Library (VHL) ), in the years 2010 to 2020, including original articles, of the case-control, ecological, sectional, and cohort types, samples of children, of both sexes, diagnosed with leukemia. Results and Discussion: Breastfeeding for a longer period does not decrease the risk of ALL because of the change in nutritional composition throughout lactation, as it is known that breast milk undergoes adaptive transitions for each phase of the baby. There is a higher concentration of proteins in colostrum and transitional milk, as well as a higher concentration of antioxidant vitamins, when opposed to mature milk, in addition to maternal nutrition, gestational age, circadian rhythm, among other factors. Final considerations: The results of the studies confirm the veracity of the beneficial effect of breastfeeding in relation to reducing the risk of childhood leukemia due to its immunological properties.Acesso AbertoLeucemiaLeucemiaCriançaInfânciaAmamentaçãoLeukemiaChildChildhoodBreast-feedingTrabalho de Conclusão de CursoCiências da SaúdeNutrição