This paper describes the design, fabrication, modeling, and early testing of a new high-sensitivity bulk-silicon micromachined accelerometer based on electron tunneling. The electron tunneling transducer permits detection of small displacements of the proof mass with high electrical response; such a transducer is essential for a high-performance miniature accelerometer. Using bulk-silicon microfabrication technology, a new tunneling accelerometer has been fabricated successfully and operated reliably. The resonant frequency of the proof mass in this tunneling accelerometer is easily modified to satisfy different requirements of sensitivity, dynamic range and bandwidth. This tunneling accelerometer is designed for underwater acoustic application and can be packaged in an 8 cm3 volume with a mass of 8 grams. The measured sensitivity is as high as 200 V/g with a resolution of less than 10 μg/, which is limited by environmental noise, from a few Hz to 270 Hz for a 360 Hz resonant proof mass.