Bioresorbable electronics that can dissolve away in aqueous environments and generate biologically safe products offer a revolutionary solution to replace the built-to-last electronics predominantly used in implanted devices and electronic gadgets. Their use can reduce the risk of surgical complications by minimizing the number of necessary surgeries, and prevent production of electronic waste by allowing rapid device recycling. This Element presents bioresorbable materials such as metals, polymers, inorganic compounds, and semiconductors that have been used to construct electronic devices, and analyzes their unique dissolution behaviors and biological effects. These materials are combined to yield representative devices including passive and active components and functional systems.