The Fontan operation is the final stage of single-ventricle palliation that effectively separates the pulmonary and systemic circulations. The procedure connects the inferior vena cava directly to the pulmonary arteries or to the previously created superior cavopulmonary anastomosis, which allows all of the deoxygenated systemic venous return to flow directly to the lungs. The single ventricle then pumps oxygenated pulmonary venous blood to the systemic circulation. Baseline higher central venous pressure drives the Fontan circulation. There is an increased incidence of severe spinal deformities in children with congenital heart disease that will require corrective surgery, including posterior spinal fusion. Anesthesia for posterior spinal fusion in Fontan patients presents significant challenges, especially as the patient is in the prone position, which further exacerbates hemodynamic instability. This chapter discusses the perioperative management of a Fontan patient for posterior spinal fusion.