Polyhydramnios is a relatively common obstetrical complication. Major causes include maternal diabetes, chromosomal disorders, isoimmunologic disease, congenital abnormalities, multiple gestations, and idiopathic reasons. Perinatal morbidity and mortality is high and maternal complications are frequent. Successful management depends upon appropriate diagnostic evaluation. Prolongation of the pregnancy for further fetal maturation may be achieved with timely therapeutic amniocenteses.