Evidence suggest huge health benefits of breastfeeding including reduced risk of infectious diarrhoea and ear infection, improved cognitive development, lower rates of obesity among mother and child, reduced risk of diabetes, hypertension, cardiovascular disease, low cholesterol, and some types of cancer. There are greater relative risks of hospitalization among formula-fed infants for a range of individual illnesses. However, breastfeeding rates are on decline globally, which includes Nepal. Some of the challenges in initiating and continuing breastfeeding include lack of skilled advice and support, perceptions surrounding pain and lack of milk, socio-economic deprivation – both regional or area specific and racial/ethnicity based, perceptions of breastfeeding as a sexual activity that socially disapproves breastfeeding in public, and role of media and market. The practices such as formulation and implementation of societal standards and legal regulations that facilitate breastfeeding; multifaceted packages including targeted, small group, interactive education programmes; complementary local interventions for targeted groups; prenatal combined with postnatal interventions and support work effectively to increase breastfeeding. This study is based on a review of literature that consists of both the empirical research and systematic literature review on breastfeeding outcomes, challenges, and good practices. The studies included for the review are open to global scale, however, some of those are purposively searched and selected from the UK and Nepal. A light touch and systematic approach was followed to search and review the literature where topic- followed by abstract- and finally full-text was reviewed. ECLIPSE and STARTLITE was used to structure the literature search and review. ECLIPSE and STARTLITE are mnemonics that are widely used in health and social care literature search and review. Based on the review an evidence map on the relationship between breastfeeding and long-term outcomes is developed. The aim of the research is to inform on the existing science and evidence-based on breastfeeding outcomes. The evidence map is intended as an easy to follow and useful resource to learn from evidence based on existing literature as well as the policy makers and implementing agencies to reflect on their existing policies, programmes and interventions on breastfeeding so as to envisage the longer-term outcomes.