Abstract : The global prevalence of low birth weight is estimated to be 15% to 20% of all births representing over 20 million births in a year. There is wide variation in the prevalence of low birth weight across regions; however, evidence shows the nearly half of low births weight occurs in low and middle-income countries and especially in the most vulnerable population. A cross sectional study was conducted among low birth weight children(0-5 years) in a tertiary care hospital, Hyderabad. Simple random sampling method was followed. A pre-tested and semi-structured questionnaire was used which comprises of socio-demographic details and anthropometric measurements. Socio-demographic factors and risk factors for low birth weight were assessed using the interview schedule. Data was coded and entered in MS Excel and statistical analysis was done using SPSS version 22 Software. prevalence of underweight among under-five children and grades of malnutrition as per IAP classification. The prevalence of underweight among under-five children was 52.9%. According to IAP classification. The prevalence of underweight among under-five children who belongs to class 1 and class 2 socio-economic status was 40% and 43.7%. Under-five children belonging to class 4 socio-economic status were more malnourished(63.4%). The birth weight was correlated with the study parameters overall and with the gender. The chest circumference (r=0.76; P<0.0001) shown a statistically significant positive correlation. The prevalence of underweight was very high in our study population. Most of the underweight children were infants, females and those who belong to lower socio-economic status. Therefore, they should be the primary targets for interventions to fight against the malnutrition.