Severe tricuspid regurgitation resulting from a flail leaflet is a rare cause of neonatal cyanosis. We report two neonates with profound cyanosis and severe tricuspid regurgitation caused by rupture of the papillary muscle supporting the anterior leaflet, without other structural heart defects. Ductal patency could not be established. Repair of the tricuspid valve was performed by reimplantation of the ruptured papillary muscle head, after initial stabilization using extracorporeal membrane oxygenation. Early recognition and treatment of this otherwise fatal condition can be lifesaving.