Conjoined twining is a rare medical phenomenon, with an overall prevalence of 1.47 per 100 000 births. This report describes a successful separation of xypho-omphalopagus conjoined twins complicated by unbalanced blood shunting through the porto-systemic anastomoses within the shared liver parenchyma. Significant extrauterine twin-twin transfusion syndrome caused by unbalanced shunting is an extremely rare, and probably under-recognized, hemodynamic complication in conjoined twins necessitating urgent separation. Progressive deterioration with a poor outcome can be prevented if the condition is recognized in a timely manner.