This Letter presents simulation, fabrication and testing of a high-performance quad-beam silicon piezoresistive accelerometer with very low cross-axis sensitivity. Cross-axis sensitivity in piezoresistive accelerometers is an important issue particularly for high-performance applications. In the present Letter, low cross-axis sensitivity is achieved by improving the device stability by placing four flexures in line with the proof mass edges. The accelerometer device is realised in a single-step double-sided bulk micromachining technique using a 5 dual-doped tetra methyl ammonium hydroxide solution as an anisotropic etchant. Test results of four fabricated devices show an average prime-axis sensitivity of 559.5μV/g/5V, a maximum cross-axis sensitivity of 0.62 full scale (FS acceleration=13g) of the prime-axis sensitivity and nonlinearity at a level of 0.5 of FS which are comparatively better than already reported devices and commercially available piezoresistive sensors. © 2012 The Institution of Engineering and Technology.