During a period of 8 years (1985-92), 100 fetuses were diagnosed to have non-immune hydrops on the basis of ultrasonographic findings and absence of rhesus isoimmunization. Both the mother and the fetus were thoroughly evaluated by a set protocol that included a detailed fetal abnormality scan with echocardiography and fetal blood sampling. A cause for non-immune hydrops could be identified in 81% of the fetuses. Cardiovascular abnormalities (23%) and alpha(1)-thalassemia (22%) were almost equally common etiological factors in the South-East Asian population under investigation. A chromosomal abnormality was detected in 10% of the fetuses with non-immune hydrops. Twenty-six fetuses were found to be suitable for in utero therapy. In utero therapy included one or more of the following: (1) fetal intravascular blood transfusion; (2) direct fetal drug therapy; and (3) fetal pleuroamniotic shunting. Eighteen of the 26 babies (69.2%) were alive and well at 1 month after delivery. It is concluded that in well-selected cases appropriate in utero fetal therapy can lead to significant improvement in fetal salvage.