Relationship of Knowledge of Breastfeeding Mothers with Breast Milk in Perlis Village, Langkat Regency Fitri Ardiani * , Albiner Siagian, Elisa Julianti, Zulhaida Lubis {fitri.ardiani@usu.ac.id 1 } Universitas Sumatera Utara, Medan, Indonesia Abstract. Breastfeeding is the ideal way of giving food to babies aged 0-6 months. Breast milk has a balanced composition that is good for growth and meets the nutritional demands of newborns. This study aimed to evaluate the association between breastfeeding moms' knowledge about breastfeeding and breastfeeding. This study is a cross-sectional observational analytic study. Breastfeeding moms with kids aged 4 to 12 months comprised the study's sample. Based on the study results, it was found that breastfeeding mothers had good knowledge of breastfeeding by 45.7%, exclusive breastfeeding by 68.6%, and mothers who had low education and gave exclusive breastfeeding by 60.8%. There was a significant association between a mother's nursing knowledge and breastfeeding and breastfeeding (sig. < 0.05). Breastfeeding mothers have various educational backgrounds and different levels of knowledge, but the majority practice exclusive breastfeeding. Keywords: knowledge about breastfeeding; breastfeeding; breastfeeding mothers 1 Introduction Nutrients have a significant role in the continuity of children's growth, development, and health. The best source of nutrients for babies in their first life is breast milk (ASI). Breast milk is the single greatest nourishment for newborns since it provides the entire nutritional content and is perfect for the growth and development of a baby. The amount of breast milk consumed, including energy and other nutrients in breast milk, will determine the growth and development of the baby. (Sugiarti, 2011) In children, breastfeeding in infants is closely related to under nutrition and over nutrition (obese). Based on the 2018 Basic Health Research (Riskesdas) results, 17.7% of children under five experienced severe malnutrition and undernourishment, 30.8% of toddlers were concise and short, 10.2% of toddlers were toddlers skinny and thin, and 8% of toddlers were obese (RI, 2007). To reduce child morbidity and mortality, Breastfeeding for at least six months is recommended by the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF). (Organization, 2003). According to Riskesdas statistics from 2018, the proportion of infants aged 0-5 months who are exclusively breastfed in Indonesia is 37%. 2 This number is still lower than the WHO objective, which requires breastfeeding coverage of up to 50 percent, which shows that very few babies are getting exclusive breastfeeding. Although breastfeeding and breastfeeding are very beneficial, it is estimated that 85% of mothers do not give breast milk optimally. It appears that exclusive breastfeeding, as recommended by WHO (2002), is still rarely practiced by mothers BIC 2021, October 11-12, Batusangkar, Indonesia Copyright © 2022 EAI DOI 10.4108/eai.11-10-2021.2319616