Hemodynamically significant systemic-to-pulmonary artery collaterals may represent an underappreciated cause of cardiorespiratory compromise in tetralogy of Fallot with absent pulmonary valve (TOF/APV). We retrospectively reviewed the angiographic, magnetic resonance imaging, operative, and autopsy reports of the 50 patients with TOF/APV managed at our institution in the past 10 years and demonstrated that at least 7 of 50 patients (14%) had significant aortopulmonary collaterals.