Prenatal lead exposure has known adverse effects on maternal health and infant outcomes across a wide range of maternal blood lead levels. In 2010, the Centers for Disease Control and Prevention issued the first guidelines regarding the screening and management of pregnant and lactating women who have been exposed to lead.  In humans, the lead is absorbed into the blood plasma where it equilibrates with the extra–cellular fluid and crosses the membranes like the placenta and the blood brain barrier. Therefore the fetus is exposed to maternal blood lead levels from the 12th week of gestation which is associated with preterm delivery, abortions etc.The present study was conducted to find the effect of maternal exposure to lead and neonatal birth weight among women living in the urban slums of Lucknow. Our study hypothesis was that lead exposure would reduce birth weight.