Among 6147 pregnancies undergoing cordocentesis during the study period, 122 twin fetuses met the study criteria and were matched with 336 singleton controls. Success rate of sampling was slightly higher in singleton than in twin gestations (98.8% vs 97.3%), and time required for the procedure was significantly longer in the twin group (8.1 vs 6.3 min, p = 0.02). Immediate complications, such as fetal bradycardia and transient bleeding from the puncture site, were significantly higher in twins (13% vs 6.0%, p = 0.001; and 34.8% vs 26.1%, p = 0.03, respectively). However, fetal loss rate within 2 weeks of cordocentesis was not different