A case-control study of preterm delivery was undertaken at the district of Qiaokou in Wuhan during October, 1987 to May, 1988. The study population consisted of 130 mothers of singleton preterm infants and 260 mothers of singleton term infants. The result of logistic regression analysis showed that significant factors of preterm delivery included low maternal stature, the young age of menarche, a previous induced abortion, a history of infertility problems, vaginal bleeding during the pregnancy, low weight gain during the pregnancy, premature rupture of membranes, hyperemesis gravidarum, and lack of antenatal care. The result also showed that psychosocial stress in pregnancy might be related to preterm delivery.