As implantable medical electronics (IMEs) developed for healthcare monitoring and biomedical therapy are extensively explored and deployed clinically, the demand for non-invasive implantable biomedical electronics is rapidly surging. Current rigid and bulky implantable microelectronic power sources are prone to immune rejection and incision, or cannot provide enough energy for long-term use, which greatly limits the development of implantable medical devices. Herein, a comprehensive review of the historical development of IMEs and the applicable miniaturised power sources along with advantages and limitations is given. Despite recent advances in microfabrication techniques, biocompatible materials have facilitated the development of IMEs system toward non-invasive, ultra-flexible, bioresorbable, wireless and multifunctional, progress in the development of minimally invasive power sources in implantable systems has remained limited. Here we summarise three promising minimally invasive power sources, including energy storage devices (biodegradable primary batteries, rechargeable batteries and supercapacitors), human body energy harvesters (nanogenerators and biofuel cells) and wireless power transfer (far-field radiofrequency radiation, near-field wireless power, ultrasonic and photovoltaic power). The energy storage and harvesting mechanism, configurational design, output power and applications in vivo are discussed. It is expected to give a comprehensive understanding of the IMEs for painless health monitoring and biomedical therapy with long-term stable function