Background: The reduction of maternal mortality and the improvement of infant survival are currently at the forefront of health issues and health sector reforms worldwide and in particular our country. Thus, efforts should be made to identify those risk factors that mitigate against achieving the above, with a view to putting in appropriate measures to combact them at all levels. Aim: This prospective study aimed to determine the relationship between maternal height, velocity of weight gain in the third trimester of pregnancy and birth-weight. It also aimed to assess their reliability in predicting low birth weight (LBW). Methods: A cohort prospective study of pregnant women in the third trimester of pregnancy involving three measurements of weight at 30, 34 and 38 weeks gestation; maternal height at booking and their babies weight at birth was conducted at two tertiary institutions in Lagos State. Analysis was done using Epi-info 2000 package