A radiation protected active implantable medical device includes an ionizing radiation shield disposed over at least one major surface of an electronics package, a microprocessor, or both contained within an AIMD housing. The ionizing radiation shield is made from a high atomic number, high atomic weight, high density material such as led, gold, platinum, iridium, tungsten or tantalum and has an atomic weight of at least 180 and a density of at least 11 grams per cubic centimeter. The ionizing radiation shield has a thickness of at least 0.25 millimeters and is preferably no thicker than 1.05 millimeters and has an overall attenuation of ionizing radiation of at least 0.5 HVL.