Background: Each year, about 20 million deliveries are Low Birth Weight (LBW) with 96.5% occurring in developing countries. The prevalence of LBW in Sierra Leone is about 7% while the Western Area Urban (WAU) district reports 17.5%. This study sought to determine factors associated with LBW deliveries in five referral hospitals in the WAU district, Sierra Leone.Methods: A hospital-based unmatched 1:2 case-control study was conducted among mothers who delivered live singleton babies from November, 2019 to February, 2020 in five referral facilities. Antenatal care cards of mothers were reviewed and a pre-tested questionnaire also administered to them. The association between maternal socio-demographic, socio-economic, obstetric and lifestyle factors and LBW was assessed using bivariable and multivariable logistic regression analyses. Results: A total of 438 mothers (146 cases and 292 controls), mean age: 24.2 (±5.8) and 26.1 (±5.5) years for cases and controls respectively participated in the study. Among mothers, 36.9 % (162/438) had no formal education, 25.8% (113/438) were unemployed and 29.7% (130/438) were unmarried. Multivariable analysis revealed that being unemployed (AoR = 2.52, 95% CI 1.16 - 5.49, p = 0.020), having anaemia during pregnancy (AoR = 3.88, 95% CI 1.90-7.90, p < 0.001), having less than two years inter-pregnancy interval (AoR = 2.53, 95% CI 1.11-5.73, p = 0.026), and smoking cigarettes during pregnancy (AoR = 4.36, 95% CI 1.94-9.80, p <0.001) were significantly associated with having LBW babies.Conclusion: Factors associated with LBW identified were unemployment, anaemia during pregnancy, < 2 years inter-pregnancy interval and cigarette smoking during pregnancy. Health care providers should screen and sensitize mothers on the risk factors of LBW during antenatal sessions.