Background: Birth weight is an important determinant of child survival and development. Low birth weight (LBW) is an index of our status of public health, maternal health and nutrition. The major challenge in the field of public health is to identify the factors influencing low birth weight and to institute remedial measures. Aim: The aim of this study was attempted to assess incidence of low birth weight and its risk factors affecting low birth weight. Materials and methods: A cross sectional study design was carried out in a tertiary care government hospital.A total of 1120 postnatal mothers who delivered in the hospital during study period were included in the study except still births. All babies were weighted on standard beam balance within 24 hours of delivery and mother’s height was measured by height measuring stand. The collected data was analyzed using statistical package for the social sciences (SPSS) version 22. Results and analysis:incidence of LBW neo-born babies was 240/1120 (21.4%)where 104 (43.3%) were males and 136 (56.7%) were female babies. Mean age of the mothers was 23.52±3.16 years; mean weight noted was 58.94±10.09 kg and mean height was 159.1±7.15 cm. The study showed associations between birth weight and mother’s age, weight, height, hemoglobin (Hb) %, birth interval, income, bad obstetric history and complications Discussion and conclusion: The incidence of low birth weight was found to be very high and it was associated with many risk factors related to maternal health and services. Hence it is recommended to improve maternal health through strengthening the existing maternal services at the basic level of community.