Serial decompressive amniocenteses were performed at 18-23 weeks of gestation in 23 pregnancies referred due to echographic signs typical of twin-twin transfusion syndrome. The procedures were repeated until delivery or permanent normalization of the amniotic fluid volume both in the donor and the recipient twin sac. The overall survival rate was 57%, but in only 39% of the pregnancies did both twins survive without handicaps. The absence of end diastolic flow in the umbilical artery of the donor twin was associated with poor chances of survival for both fetuses; in contrast, the presence of hydrops or ascites in the recipient twin did not worsen the prognosis. A policy of aggressive amniotic fluid decompression may achieve permanent resolution of the fluid in over 50% of the pregnancies complicated by twin-twin transfusion syndrome.