The paper elaborates the Silicon Nanowire arrays fabrication using standard CMOS compatible technologies (top-down) with each array consisting of 100 wires, which are individually electrically measurable for their conductance and facilitating statistical analysis. The arrays are integrated with micro-fluidics for the delivery of various chemicals for surface modification, buffer solutions, biomolecules/ analytes, etc. Biotinylated-ssDNA is detected electrically, label-free by the nanowire sensors modified by streptavidin; further DNA hybridization is also observed similarly on sensors modified by complementary DNA probes. Our approach paves way for realizing high-density, highly sensitive biological and chemical sensors using mass fabrication technologies and thus has the potential to achieve multiplexed detection which is essential for understanding and curing of complex diseases. ©2007 IEEE.