BACKGROUND – Pre-eclampsia is associated with high maternal and perinatal morbidity and mortality especially in the developing countries. It is the leading cause of iatrogenic prematurity worldwide. OBJECTIVE – To assess the effect of routine Calcium supplementation during pregnancy on pre-eclampsia among primigravidae . METHOD - This is a randomized controlled double blind study involving a total of 420 healthy eligible primigravidae who were below 20 weeks of pregnancy and whose written informed consents have been obtained and were randomized by computer generated number at booking between 27th April, 2010 and 29th July, 2010 into two groups: Calcium group n=210 and placebo group n=210. Early ultrasound scan was done for them to confirm and date the pregnancy. Each participant was given 1.2g of elemental calcium or placebo depending on the group, to be taken daily in two divided doses till delivery. The medications were prepacked identically and dispensed at the hospital pharmacy with the routine haematinics. The previous packs were checked in the next visit to assess compliance. Each subject was seen according to the routine antenatal clinic schedule. Blood pressure and proteinuria were evaluated at each visit. Each patient was followed up till delivery and discharge from the hospital.