Background There is an overwhelming body of evidence strongly suggesting that periodontal infection may have a significant negative impact on pregnancy outcome in some women. The aim of this study was to determine the association between periodontal disease and preterm low birth weight of babies.Materials and Methods A total of 300 pregnant women, between 20 and 24 weeks of gestation i.e., second trimester, were considered for the study. The periodontal status was recorded using the following parameters: probing pocket depth, clinical attachment level, oral hygiene index and plaque index. After initial examination in the second trimester, the pregnant women were followed till delivery of the baby. Postpartum data i.e., weight of baby, gestational age of pregnancy and type of delivery, were recorded. Results Out of 300 pregnant women, 248 women had fullterm delivery (12 low birth weight and 236 normal birth weight) while 52 had preterm delivery (6 normal birth weight and 46 low birth weight). There was significant association between body mass index and level of periodontal disease severity of pregnant women with birth weight of babies, gestational age of pregnant women and mode of delivery, respectively. As the level of periodontal disease severity increased, the proportion of delivering preterm and low birth weight babies also increased.