This retrospective study was carried out on 78 women with gestational diabetes during Nov. 1982-Oct. 1991. The study indicates that treatment of gestational diabetes can reduce the occurrence of macrosomia. Macrosomia occurred in 19.35% of the insulin-treated group, 21.05% of the diet-treated group, and 50% of the untreated group. Neonatal morbidity was decreased in good diabetic control group. A routine prenatal "50g glucose screen" in pregnant women with high-risk factor should be carried out in order to make early diagnosis of gestational diabetes. Delivery time should be choosen during 38-40 weeks of gestation.