Low birth weight is an important public health indicator because of the strong association between birth weight and infant mortality and morbidity. The objectives were to determine the frequency of low birth weight, to describe the sociodemographic characteristics, to determine the risk factors associated with low birth weight and to determine the neonatal prognosis in the gynaecology and obstetrics department of the reference health center in Commune I of the Bamako district. Material and Methods: This was a cross-sectional, descriptive and analytical study in the department from 31 December 2020 to 30 June 2022. We carried out exhaustive sampling, taking into account all live newborns with a low birth weight. All newborns born in the department weighing between 500g and 2499g during the study period were included. Results: We recorded 4,292 births, 180 of which were low birth weight, giving an overall incidence rate of 4.2%. Of the 180 low birth weight babies, we found 111 cases of prematurity (61.7%) and 69 cases of hypotrophy (38.3%). We found that the proportion of low birth weight babies was higher in the young mothers in our study, at 60.5% for the under-19 age group. Our study showed that the extreme ages of the mother were a factor favouring or even predisposing to the occurrence of low birth weight. We noted a high frequency of primiparous women (38.7%) followed by multiparous women (32.5%). Other maternal risk factors included hypertension (8%) and a body mass index of less than 18.5% kg/m2 in 41.2% of cases. Half of the new borns (47.8%) weighed between [1501-2000g]. Among the transferred newborns, 53.3% received kangaroo mother care and 6.8% of the newborns died during the first thirty days of life. We recorded a mortality rate of 6.8%. Conclusion: Low birth weight is a public health problem because of its high prevalence and its harmful consequences, especially for infants.