The study aims to determine the exclusive breastfeeding rate of mothers with children under 24 months of age who came for examination and treatment at Thai Nguyen National Hospital and analyze a number of related factors. A cross-sectional descriptive study was used by face-to-face interviews with 220 mothers who were nursing infants under 24 months of age and were treated at the general pediatrics department, Thai Nguyen National Hospital from June 2021 to June 2022, according to the sampling procedure. A single random sample was taken from the list of hospitalized patients. Research results show that the rate of exclusive breastfeeding is very low, namely: at 6 months: 13.2%; 5 months: 30.9%; 4 months: 37.7%; 3 months: 44.1%; 2 months: 54.4% and 1 month: 62.3%. There is a relationship between exclusive breastfeeding and postpartum counseling by healthcare medical staff and mothers with correct general knowledge about exclusive breastfeeding. It is necessary to improve the knowledge and skills of counseling for the medical staff and the knowledge of breastfeeding in the first 6 months for women of reproductive age.