A case-control study on preterm delivery was conducted in Jianan and Jianhan District, Wuhan City in 1988. 130 singleton preterm infants were included with 260 term infants as control. The results showed that the risk factors in prematurity were edema-proteinuria-hypertension syndrome (OR 1.8), maternal diseases in pregnancy (OR 1.6), hyperemesis gravidarum (OR 5.1), vaginal bleeding during pregnancy (OR 2.4), premature rupture of membranes (OR 3.6), low weight gain and low average weight gain per week during pregnancy, psychosocial stress during pregnancy, inadequate prenatal care, maternal stature less than 158 cm (OR 1.7), menarche before age 12 (OR 4.3), multi-gravida (OR 2.1), previous induced abortion (OR 2.1) and passive cigarette smoking during pregnancy. The author suggests that early treatment of complications of pregnancy and forcing prenatal care should be emphasized in order to reduce the incidence of preterm births.