Birth weight of a newborn is an important predictor of its chance of survival and physical and mental growth. The various obstetric, psychological, socio-economic, demographic and maternal morbidity related factors can affect the birth weight. The present study was conducted to nd out the proportion of low birth weight babies among the babies born at tertiary care hospital and to nd out association between various Socio-economic and demographic factors and birth weight. The present cross-sectional study was conducted during the period 1st Dec. 2021 to 31st Jan. 2022 among 390 mothers admitted in post-partum ward after delivery and fulll the inclusion criteria. Descriptive statistics and Chi-square test were applied for analysis. In the present study, proportion of LBW was 27.4%. LBW percentage was higher among illiterate mothers, mothers engaged in agriculture work, mothers belonged to scheduled caste and lower socio-economic class. LBW percentage was higher among illiterate mothers, mothers engaged in agriculture work and mothers belonged to scheduled caste and lower socio-economic class. The nding of study emphasized on improvement of female education. Higher education status can help in getting better occupation opportunity and in improving the socioeconomic status of the family