Electrical conductivity and viscoelastic properties of polymer nanocomposites play key roles in determining their piezoresistive behavior. In the present work, the piezoresistive behavior of polymer blend nano composites composed of Thermoplastic polyurethane (TPU),poly (styrene- ethylene-butylene-styrene) block copolymer (SEBS) and multi-walled carbon nanotubes (MWCNTs), fabricated by melt mixing process was studied. The blend nanocomposite samples with different blend ratios and MWCNTs loadings were considered. The melt viscoelastic results, measured in terms of storage modulus in low frequency range, showed a stronger 3D network of MWCNTs in TPU, compared to that in SEBS, indicating greater dispersing ability for TPU. The morphological observations showed that SEBS remains as dispersed phase even in TPU/SEBS 50/50 blend. More interestingly, SEBS particle size were found to be unchanged with increasing SEBS content. These results could be explained in terms of high melt elasticity of SEBS phase which could minimize the coalescence effect. The MWCNTs were preferentially localized in TPU phase leading to electrical percolation threshold of 1.5 - 2 weight percent depending on blend ratio. The piezoresistive behavior of blend nanocomposites changed from positive to negative by increasing the MWCNTs concentration. It was also demonstrated that increasing the the SEBS content acts in the favor of piezoresistive stability while reduces the piezoresistive sensitivity. This provides a good method to design different piezoresistive systems for strain sensor applications.