An acardiac twin is the most severe form of the twin-to-twin-transfusion sy
ndrome. The pump twin is at high risk for congestive heart failure. Various
invasive procedures have been developed to occlude the major Vessel in the
acardiac twin. We describe successful interruption of blood flow to the ac
ardiac twin with monopolar thermocoagulation at 24 weeks' gestation. The he
althy twin was delivered at term.