With the development of wearable electronic, optoelectronic and sensing devices, stretchable conductors hold the promise for transforming the current technologies. There is substantial interest in realizing the stretchable conductors of polymer nanocomposites with metal/carbon nanomaterials. In this study, we report on a new water-based synthetic route for fabricating stretchable electrodes composed of Ag nanoparticles (NPs) and single-walled carbon nanotubes (SWNTs) embedded in a polymer matrix. The Ag NPs and SWNTs were uniformly dispersed in water with polymer surfactant, poly(acrylic acid). The mixture solution is subsequently incorporated into a polyurethane aqueous solution. With this aqueous approach, stretchable and conductive films were fabricated on polydimethylsiloxane substrate, with the conductivities of 600 and 120 S/cm in unstrained and 90% strain conditions, respectively.