One of the most rare and dangerous complications of a modified Blalock-Taussig shunt involves the formation of a pseudoaneurysm. A pseudoaneurysm may rupture or may result in other adverse events including compression of mediastinal structures or collapse of the underlying lung parenchyma. Shunt-related pseudoaneurysm may be associated with shunt occlusion, bacteremia, or pulmonary hemorrhage. We describe two cases complicated by large pseudoaneurysm formation, following systemic-to-pulmonary artery shunt operations. The patients in question had recurrent pulmonary hemorrhage. Both underwent successful placement of covered coronary artery stents.