Objective : To determine whether maternal BMI predicted low birth weight. Methods : A total of 185 antenatal women who presented in first trimester in antenatal opd for regular check up in were included in the study and were followed up till delivery. Detailed history and examination done after getting informed consent. The height was recorded by a stadiometer and weight by standard weighing machine and BMI was calculated. The birth weight of the baby taken immediately after delivery and recorded. Statistical analysis was done by EPI2005 package. Results : Among 185 women studied 48.6% of them were undernourished. There was a significant association between low BMI and low birth weight.