Transcatheter pulmonary valves are being used off-label to treat pulmonary insufficiency in patched right ventricular outflow tracts (RVOTs). We describe the first reported cases of patched RVOT rupture, during balloon sizing for percutaneous pulmonary valve implantation, in two patients with tetralogy of Fallot status post repair. Both RVOTs were too large for subsequent catheter-based intervention. The ruptures remained stable over time, and both patients were managed conservatively with follow-up imaging. © 2015 Wiley Periodicals, Inc.