SU-8 is being increasingly used as a compliant structural material for MEMS applications due to its interesting properties such as lower Young’s modulus and higher mechanical and thermal stability. One of the popular classes of MEMS devices is a piezoresitive microcantilever. Ultra-sensitive polymer composite cantilevers made up of SU-8 as a structural layer and 10% carbon Black in SU8 as a piezoresistive layer with lower Young’s modulus and higher gauge factor have been reported recently by our group. Higher electrical conductivity at lower concentration of conductive filler is of increased interest. Here we report a novel composite with purified multiwall carbon nanotubes (MWNT) in SU8 as a piezoresistor. MWNT were modified with octadecyl triphenyl phosphonium bromide (OTPB) in order to achieve debundled MWNT. A microcantilever device with integrated MWNT/SU-8 composite has been fabricated and characterized.