Inertial MEMS piezoresistive acceleration sensors have found a wide range of applications in last four decades. This paper presents design and simulation of a doubly clamped acceleration sensor with integrated piezoresistors. Prime objective of this work is to enhance the electrical sensitivity of the sensor. In this regard, silicon nanowire (SiNW) based piezoresistors are deposited at the fixed end of the beams where maximum stress is experienced when the beam undergoes deformation. The complete device with integrated piezoresistors is virtually fabricated using a finite element method (FEM) based computer aided design (CAD) tool IntelliSuite®. For analysis, SiNW piezoresistors with two diiferent widths of 35 nm and 140 nm with a length and thickness of 2 μm and 40 nm respectively are considered. Results show that the device integrated with a 35 nm width piezoresistor depicts 1.36 times and 2.51 times more sensitivity than the devices with 140 nm width SiNW and bulk piezoresistors respectively. © 2016 IEEE.