Background: Birth weight is the single most important factor determining survival, healthy growth and development of a newborn. Low birth weight (LBW) is one of the most serious challenges in maternal and child health in our country. Objectives: To determine the proportion of LBW babies among hospital births and study various maternal sociodemographic factors which might be associated with birth weight. Methods: This cross–sectional study was carried out at a tertiary care hospital in Gurugram, Haryana from 1st July 2015 to 30th June 2016. All live born infants satisfying the inclusion criteria and their mothers were included in the study. Statistical analyses were performed using SPSS Version 20.0. Results: In this study, 30.32% mothers delivered LBW babies. Proportion of LBW was comparatively higher among babies born to mothers who were below 20 years of age (60.46%), illiterate (50.0%), engaged in unskilled work (52.32%), belonging to low socioeconomic class  (61.54%), living in a 3–generational family (39.62%) and Muslim by religion (36.06%). Maternal education, maternal occupation, socioeconomic status and type of family were found to be significantly associated with LBW on multivariate analysis. Conclusion: Improving some modifiable socio–demographic variables like female literacy and socioeconomic status of mothers would go a long way in reducing the incidence of low birth weight in India.