Two hundred and sixteen diagnostic cordocenteses were performed using the following technique: A guide was used to deliver the distal end of the needle to the immediate vicinity of the umbilical cord, after which the needle was released from the guide and a free-hand technique was used to enter the umbilical cord. The vessel punctured was identified by its sonographic appearance and flow direction using color Doppler technology. All procedure-related losses which occurred within 2 weeks were analyzed. The gestational age at the time of cordocentesis ranged from 18 to 42 weeks. Most punctures (62%) were performed at the placental insertion of the umbilical cord. In 32% of fetuses the free-floating loop was sampled and in 6% the puncture was performed at the site of cord entry into the fetus. Two fetuses died shortly after cordocentesis. One death occurred at 28 weeks in a fetus with severe cytomegalovirus infection. The other death was due to premature rupture of the membranes after the procedure in a very premature fetus. The overall fetal loss rate was 0.93%. In conclusion, the combination of the two cordocentesis techniques appears safe and highly successful in obtaining fetal blood samples.