The birth weight of an infant is the single most important determinant of its chances of survival healthy growth and development. Because birth weight is conditioned by the health and nutritional status of the mother, the proportion of infants born with low birth weights (LBW) closely reflects the health status of the communities into which they are born.It is clear from the many causes that there is no single line of management to LBW. Prenatal care, nutritional programs, health education on the need of pregnant women, family planning, and measures aimed at improving the health and nutrition of young girls affect the management. We have reported the incidence of LBW among babies born in Zagazig University Hospitals with predominancy to prematurely born infants (81%).The highest incidence is among the group of low birth weight between 1.500 and 2.5000 kg. (52.2%). There is no relation between birth weight and the gender of the baby. The gestational age of LBW babies ranged between 27 & 40 weeks, while the gestational age of normal birth weight babies was ranged between 37 and 40 wks. The incidence was high among multiple pregnancies (either twin or triplets).The first baby was the most susceptible one to low birth weight among other siblings. The maternal gravidity was ranged between (1 – 6) siblings. As well as the maternal parity (1 – 6), all women in this study were of low socio-economic standard. The multiple birth (twins or triplets) showed the highest incidence of LBW incidence (46.7%).There was no relation between LBW and consanguinity. The maternal education has a very important role in reducing the incidence of low birth weight as the highest value is present among babies of low educated mothers (58.7%). The maternal work has no harmful effect on the baby weight as the working mother relieves by her work from her exhausting daily duty at home & also the mother work relieves the mother from the emotional stress, because many of mothers in this study were living with the husband families at the same house with poor nutrition and lack of proper antenatal care.The incidence of LBW babies was the highest among mothers who have no systemic disease (86.4%) which mean that most of the mothers didn’t obey to proper antenatal care to detect the main cause of LBW. The incidence LBW babies of hypertensive mothers was the highest among other maternal systemic diseases. Also babies of preclamptic mothers showed the highest incidence of LBW among other obstetric complications.