This paper presents piezoresistive nanowires based pressure sensor with a novel and low-cost nanowire fabrication technique. Silicon nanowire sensing element (width<100 nm) is chosen because of their higher piezoresistive coefficient compared to bulk silicon and integrated into MEMS diaphragm to measure pressure up to 2 bar. The novelty of the proposed process lies in making nanowires with controllable dimensions (CD < 100 nm) and with no dependency on the lithography tool limitations. Initially, this process is optimised for nanowires and then simulations are carried out for the pressure sensor. Simulation results are presented for a pressure sensor having a diaphragm thickness of 10 μm and the sensor fabrication is currently ongoing. Proposed nanowire fabrication process can potentially be utilized to obtain any nano-dimension structure without using expensive masks and special lithography tools. © 2017 IEEE.