Unusually long and highly porous silver nanowires (Ag NWs) are prepared via a simple but novel thermal evaporation process with substrate placed below the heated filament. Ag NWs growth processes are carefully monitored with respect to the time of vapour deposition keeping the filament-substrate distance fixed at 2 cm. As-prepared Ag NWs are analyzed by transmission electron microscopy (TEM), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), optical absorption and surface enhanced Raman scattering (SERS). The present method for porous Ag NWs preparation has realized perhaps one of the best building blocks applicable to plasmonic waveguiding, nanophotonics and electrochemistry. (C) 2014 Elsevier B.V. All rights reserved.