The left internal mammary artery (LIMA) is a widely used conduit during coronary artery bypass graft surgery because of its excellent long-term patency. Although large LIMA side branches are typically ligated during the surgery, the occurrence of a coronary steal phenomenon related to these side branches following surgery remains controversial. A variety of devices, including coil embolization and gelatin sponge particles, have been used in the percutaneous treatment of LIMA side branch induced coronary steal. The Amplatzer Vascular Plug has recently been applied in variety of clinical situations, including the occlusion of aortopulmonary collaterals, patent ductus arteriosus and pulmonary arteriovenous malformations. The Amplatzer Vascular Plug is a self-expandable, cylindrical device made from nitinol that offers several potential advantages in this setting including ease of delivery, a wide range of device sizes and the ability to safely remove the device if placement location in not optimal. In this case report, we present a patient with objective ischemia in the left anterior descending artery distribution secondary to coronary steal from a large LIMA side branch that was successfully treated using the Amplatzer Vascular Plug.