Twin-to-twin transfusion syndrome represents a dilemma for both diagnosis and management. It has recently been suggested that a difference in contrast on B-mode ultrasound between the placentas is pathognomonic for the syndrome. We describe a case of monochorionic diamniotic twins with normal growth in one twin, the other showing features of stuck twin syndrome. In this case, although the contrast difference between the placentas was marked, twin-to-twin transfusion syndrome was ruled out, rendering this sign unreliable for diagnosis. Furthermore, evaluation of the stuck twin showed excessive adrenal artery flow, a feature that has been described in connection with poor antenatal and neonatal outcome. In this case, serial Doppler ultrasound evaluation of both fetuses enabled optimal timing of delivery.