A novel hybrid-integrated fiber optic accelerometer, based on Michelson interferometry, is developed. It makes use of a seismic mass suspended by a transduction fiber in a mass support. The Michelson interferometer is realized by a symmetrical double Y-branching waveguide and three polarizers, which are monolithically integrated on an x-cut, y-propagating LiNbO3 substrate with dimensions of X×Y×Z = 2×38×6 mm. On the distal endfaces of both interferometric arms, high-reflectance aluminum films are directly coated and serve as reflecting mirrors. An alternating current phase tracking (PTAC) homodyne scheme has been employed to process the signal. The performance of a prototype of the accelerometer is characterized. The measured frequency spectrum is in good agreement with the theoretical prediction.