A low birth weight (LBW) newborn is one who weighs less than 2,500 grams at birth. Birth weight is described as the main determinant of survival chances in newborns. Low birth weight is associated with infant mortality and postpartum health complications. The aim of our study was to evaluate the factors contributing to low birth weight in newborns in the Markala Health District. Patients and Methods: We conducted a descriptive, quantitative cross-sectional study in the Markala Health District. This study included newborns weighing less than 2,500 g at birth who were born and/or cared for in a health facility in the Markala District during the data collection period. Newborns weighing less than 2,500 g at birth and coming from another health district were not included. Sampling was non-probabilistic and exhaustive: all low birth weight newborns treated in health facilities in the Markala district during the collection period were included, as far as possible. The main data collection tool in this study was a structured questionnaire, developed on the basis of the specific objectives of the research. Data were collected over a three-month period after birth, from May to August 2025. Results: The study identified several factors associated with low birth weight, including twin births (25.4%), young maternal age (22.8% among 15–19-year-olds) and medical conditions such as high blood pressure (17.5%) and malaria (10.5%). The average weight of low birth weight newborns was 1964.58 grams, with a mode of 2000. The standard deviation was 402.972. The sex ratio favoured females, at 51.8%. Mothers aged 30 to 34 were the most represented, at 25.4%, followed by the two extreme age groups, 15-19 and 35-39, at 22.8% each. Conclusion: This study identified factors associated with low birth weight, the main determinants being twin births, teenage mothers, high blood pressure, infections, malaria and low attendance at prenatal consultations.