Background: The World Health Organization (WHO) recommended exclusive breastfeeding for the first six months of life, and continued breastfeeding until the age of 2 years and even beyond depending on the mother's wishes. Objective: Assess the knowledge of mothers on the practice of exclusive breastfeeding. Patients and Method: This was a prospective and descriptive study for 4 months from July 2019 to October 2019 performed in the pediatrics department of N’Djamena Mother and Child University Hospital about mothers’ knowledge and practice of exclusive breastfeeding. Studied variables were: profile of breastfeeding mothers, profile of infants, and type of breastfeeding and mothers' knowledge of exclusive breastfeeding. Results: 203 Mothers were interviewed. The age group from 20 to 30 years represented 70%. Mother’s characteristics were: married (97%), housewives (64.5%), unschooled (35.5%). Infant’s characteristics were: male (55.7%), mean age (27.29 days). Predominant breastfeeding was the main type of breastfeeding with 50.2%. Hypogalactia was the main reason for mixed or artificial breastfeeding with 22.1%. Lack of milk flow was the main reason (23.1%). One hundred and forty-four mothers (70.9%) had not received any information about exclusive breastfeeding. According to 32% of mothers, exclusive breastfeeding was of no benefit. The majority of mothers (91.6%) knew the sign of an effective breastfeeding. Conclusion: Breast milk is better and more suitable than any other replacement milk for newborns and infants. The overall results of our survey show that the exclusive breastfeeding is only practiced in a small proportion.