This paper reviews the state-of-the-art in vibration energy harvesting for wireless, self-powered microsystems. Vibration-powered generators are typically inertial spring and mass systems. The paper discusses the three main transduction mechanisms: piezoelectric, electromagnetic, and electrostatic. Piezoelectric generators use active materials to generate charge when stressed. Electromagnetic generators use electromagnetic induction from relative motion between a magnetic flux gradient and a conductor. Electrostatic generators use relative movement between electrically isolated charged capacitor plates to generate energy. The coupling factor of each transduction mechanism is discussed, and all devices are summarized in tables classified by transduction type. The paper also discusses the fundamentals of kinetic energy harvesting and the different transduction mechanisms used in generators. It reviews the performance of various piezoelectric generators, including impact coupled, resonant, and human-based devices. The paper also discusses the design and performance of various piezoelectric generators, including cantilever-based, bi-stable, and microfabricated devices. The paper concludes that the suitability of various techniques depends on the application and the characteristics of the environment. The paper also discusses the use of piezoelectric generators in human-powered applications, including shoe insoles and orthopaedic implants. The paper also discusses the use of piezoelectric generators in in vivo applications, such as blood pressure monitoring. The paper concludes that piezoelectric generators have the potential to provide a sustainable power source for wireless microsystems.This paper reviews the state-of-the-art in vibration energy harvesting for wireless, self-powered microsystems. Vibration-powered generators are typically inertial spring and mass systems. The paper discusses the three main transduction mechanisms: piezoelectric, electromagnetic, and electrostatic. Piezoelectric generators use active materials to generate charge when stressed. Electromagnetic generators use electromagnetic induction from relative motion between a magnetic flux gradient and a conductor. Electrostatic generators use relative movement between electrically isolated charged capacitor plates to generate energy. The coupling factor of each transduction mechanism is discussed, and all devices are summarized in tables classified by transduction type. The paper also discusses the fundamentals of kinetic energy harvesting and the different transduction mechanisms used in generators. It reviews the performance of various piezoelectric generators, including impact coupled, resonant, and human-based devices. The paper also discusses the design and performance of various piezoelectric generators, including cantilever-based, bi-stable, and microfabricated devices. The paper concludes that the suitability of various techniques depends on the application and the characteristics of the environment. The paper also discusses the use of piezoelectric generators in human-powered applications, including shoe insoles and orthopaedic implants. The paper also discusses the use of piezoelectric generators in in vivo applications, such as blood pressure monitoring. The paper concludes that piezoelectric generators have the potential to provide a sustainable power source for wireless microsystems.