We present our experience in the management of fetuses diagnosed with huge cardiac tumors. These cases illustrate that the size of the tumor likely does not impact on survival as much as the location of the tumor and how it compromises blood flow into and out of the ventricles. We speculate that obstruction of right-sided inflow and/or simultaneous obstruction to outflow from both ventricles may lead to diminished cardiac output, atrial and caval hypertension, and hydrops fetalis. Obstruction can occur at any point in gestation and depends on both the size and the location of the tumor in relation to all cardiac structures. We therefore suggest serial assessment of these fetuses throughout gestation, particularly after the point of postnatal viability, to assess the hemodynamic effects that the tumor has on the heart. If obstruction to blood flow and/or early fetal compromise is noted, then the decision of whether to deliver early can be made. At the time of birth, if obstruction to blood flow persists, surgery can be considered, keeping in mind that the natural history of these tumors is to shrink and become clinically less important over time.