BACKGROUND: Low birth weight, as defined by the WHO, refers to the weight of a neonate below 2500 g at birth and is a significant public health concern globally, with both short- and long-term consequences. Despite the significance of low birth weight as a public health indicator, information gaps persist. Identifying at-risk mothers requires an understanding of the risk factors associated with low birth weight. Therefore, this study aimed to determine the common determinants of low birth weight among neonates born at public hospitals in Southern Ethiopia. METHODS: An unmatched case-control study was conducted among 258 neonates (86 cases and 172 controls) born at public hospitals between 15 April and 25 May 2022. The study participants were selected using a consecutive and systematic sampling technique. Data were analysed using Stata V.14, and a multivariable logistic regression model was performed. Statistical significance was declared at a p value<
0.05. RESULTS: A total of 86 birth records of neonates with low birth weight and 172 birth records of neonates with normal birth weight were reviewed. The results revealed that lack of iron and folic acid supplementation (adjusted odds ratio (AOR) 2.47
95% CI 1.16 to 5.25), lack of additional meal intake (AOR 2.66
95% CI 1.16 to 6.00), anaemia (AOR 3.45
95% CI 1.63 to 7.28), pregnancy-induced hypertension (AOR 2.49
95% CI 1.04 to 5.97), mid-upper arm circumference (MUAC) (AOR 6.74
95% CI 2.87 to 7.00), gestational age at first antenatal care (ANC) of ≥24 (AOR 7.31
95% CI 3.43 to 15.58) and minimum food diversity (AOR 4.2
95% CI 1.94 to 9.20) were common determinants of low birth weight. CONCLUSION: Lack of iron and folic acid supplementation, additional meal intake, being anaemic, pregnancy-induced hypertension, gestational age at first ANC visit, MUAC ≤23 and minimum food diversity were common determinants of low birth weight. Initiating ANC services for all mothers and evaluating different risk factors may help to reduce low birth weight.