Wireless biosensors can integrate with biological systems and transmit signals to terminals without using tethered wires. This remarkable capability can underpin pervasive healthcare in medicine and promote numerous fundamental studies in biology. Our group establishes the wireless communication between a transmitter and a receiver through magnetic field. Specifically, the transmitter is a battery-less and chip-less magnetic structure in small scale, and the receiver consists of elements to measure the magnetic fields. The resulting system—magnetic micromechanical bioelectronics—is especially suitable for biomedical applications, due to the inherent 'transparency' of biological tissues to magnetic fields. We use the magnetic micromechanical bioelectronics as wearables or implants to provide quantitative, continuous monitoring of a wide range of biophysical and biochemical conditions.