We report a teenager with Marfan syndrome who presented to Cincinnati Children's Hospital Medical Center as part of a preoperative evaluation for an orthopedic procedure after asymptomatic arrhythmia was recognized. Continuous cardiac monitoring showed frequent premature ventricular contractions and nonsustained runs of ventricular tachycardia. Cardiac magnetic resonance imaging showed left ventricular noncompaction (LVNC), prompting insertion of an implantable cardiac defibrillator. Although Marfan syndrome is associated with cardiac lesions, it has not previously been described with LVNC. Likewise LVNC has been seen in association with other cardiac lesions; however, this report represents the first reference of LVNC in the context of Marfan syndrome.