Experience in fetal invasive therapeutic procedures is currently nearly entirely based on animal experimental research. Structural defects in the human fetus which are potentially amenable to intrauterine surgical treatment are obstructive uropathy, hydrocephaly and diaphragmatic hernia. The results from closed procedures such as shunting of urine or CNS fluid to the amniotic fluid compartment under ultrasound monitoring is as yet not very encouraging. This is partly determined by technical inadequacies, and partly due to insufficient information available on the possible presence of associated anomalies and functional aspects of the affected organ systems. The risks of invasive procedures for the mother and in particular the fetus must be weighed up against the advantages for the fetus if surgery has been successful. It seems that the development of open surgical procedures will determine the future of fetal surgery.