This chapter provides an in-depth exploration of the interface circuits designed for a variety of CMOS biosensors including voltammetric, impedimetric, capacitive, field-effect transistor (FET)-based, optical, magnetic, nuclear magnetic resonance (NMR), and temperature sensors as well as neural stimulation/recording systems. Each section of the chapter is designed to provide a comprehensive understanding of the circuits that drive these various CMOS biosensors, illustrating their significance in modern biochemical technologies.