We present the case of a 22-year-old man with a congenital mixed aortic valve dysfunction who underwent cardiac Magnetic Resonance Imaging (MRI) for the assessment of aortic valve morphology and function prior to valve replacement. Cardiac MRI showed a four-leaf-clover aortic valve morphology, the typical presentation of a quadricuspid aortic valve. The patient underwent a successful Bentall procedure to replace the aortic valve, aortic root and ascending aorta. This case report illustrates the MRI findings of a quadricuspid aortic valve with associated aortic stenosis and regurgitation.