Background: Work related factors have been suggested to adversely impact outcomes of pregnancy. The aims of this study were to compare neonatal birth weight in employed and non-employed women and to investigate the relation of 5 common occupational factors including working hours, shift work, standing, bending forward, and physical workload intensity to neonatal birth weight. Methods: This cross sectional study was carried out on 370 pregnant women, 185 employed and 185 non-employed. Information were collected about working conditions including working hours, shift work, standing, walking, bending, squatting, physical workload intensity, socio -demographic characteristic, as well as obstetric history of each patient by interview. Association between maternal occupational activity and neonatal birth weight was adjusted for medical and obstetric, occupational details were studied using logistic regression analysis.