8 cases of hemoglobin Bart's hydrops foetalis syndrome were studied, 5 male and 3 female. Duration of pregnancy was 30~40 weeks, body weight 1,000~3,500g (mean 2,000 g). 5 cases were born alive but died within 5~30 minutes after birth. 2 were stillbirths. The patients' parents were all from Guangdong Province except one mother from Hebei. Typical clinical features were observed in 7 cases' only one case had mild anemia. 7 cases had marked hepatomegaly, 4 cases had splenomegaly, 2 had slight jaundice and 1 skin ecchymosis. All cases had macro-placenta, weighing 1,100~1, 700 g (mean 1, 570 g). Laboratory findings: hemoglobin 3 . 5~11 . 1 g/dl; reticulocytes 3.8~48.5% in 6 cases.All cases showed erythroblastosis and abnormal Thalassemia-like erythrocytes accompanied with hypochromic macro-erythrocytes. Sickling test and isopropanal test were positive in 6 cases. Hemoglobin Bart's concentration was 80.6 ~90.4 % , hemoglobin portland 9.6~19.4% and alkali-resistant hemoglobin 32.2~76.0 %. Postmortem study of 6 cases revealed extramedullary erythropoiesis. Patients' parents were shown to be heterozygous α-Thalassemia 1. The father of 1patient and the mother of another case probably were double heterozygous α-Thalassemia 1/β -Thalassemia. The mothers of 6 cases suffered from toxemia of pregnancy and of 2, hypertension of pregnancy.