Breastmilk (ASI) is the best food a mother can give to her baby. The composition in breast milk is suitable for the growth and development of the baby at any time, breast milk also contains protective substances that can prevent the baby from various infectious diseases. From an economic point of view, breastfeeding is also very beneficial for both families and the country. The purpose of this study was to determine the relationship between knowledge and attitudes of mothers with exclusive breastfeeding at the Poskesdes Lobu Assist in 2020. Exclusive breastfeeding is that babies are only breastfed for 6 months without additional fluids, such as formula milk, oranges, honey, tea water, and water. white, and without the addition of solid foods, such as bananas, milk porridge, biscuits, rice porridge, and team rice, except vitamins, minerals and medicines. The type of research in this study was analytic with a cross sectional research design. The population in this study were all mothers who had babies aged> 6 months -24 months as many as 40 people at the Poskesdes Lobu Help in 2020. The results of the study were there was a relationship between maternal knowledge and exclusive breastfeeding. at the poskesdes Lobutolong in 2020 with a value of p = 0.02, namely p value <0.05. There is a relationship between maternal attitudes and exclusive breastfeeding at the poskesdes Lobutolong in 2020 with a value of p = 0.00, namely p value <0.05. It is hoped that knowledge insights will increase and change the attitudes of mothers at the Lobutolong Poskesdes in 2020 regarding exclusive breastfeeding.