A low-noise and low-power signal conditioning circuit with narrow bandwidth is presented. The circuit cascades three stages. A high current and low supply voltage amplifier as the first stage decreases the thermal noise and power consumption. A differentiator and an integrator are used as the second and third stages to reach the amplification with a narrow bandwidth suitable for microelectromechanical systems. Moreover, the first and the second stages are chopped with two different frequencies to remove their flicker noise. The circuit is designed in a 0.13 μm CMOS technology with a 1.2 V and 0.4 V supplies. The simulated power consumption is 7 μW, the gain is 55 dB, and the bandwidth can be tuned to 3.7 kHz, 1.9 kHz and 0.24 kHz. The input noise floor is 14.4 nV/√Hz.