Porous nanocomposites are prepared by electrospinning blended polyacrylonitrile, copper acetate and mutiwalled carbon nanotube in N, N-dimethylformamide. The electrospun nanofiber webs are oxidatively stabilized and then carbonized resulting in composite carbon nanofibers. The study reveals that composite nanofibers with relatively smooth surface morphology are successfully prepared. X-ray diffraction is used to confirm the presence of Cu in carbon nanofibers. The carbon nanofibers with CNTs have better thermal stability and higher electrical conductivity. The Brunauer-Emmett-Teller analysis reveals that C/Cu/CNTs nanocomposites with mesopores possess larger specific surface area and narrower pore size distribution than that of C/Cu nanofibers. The electrochemical properties are investigated by cyclic voltammetry and galvanostatic charge-discharge tests. The nanocomposite with 0.5 wt.% CNT loading exhibits an energy density of 2 Whkg(-1), power density of 1916 Wkg(-1), a specific capacitance of about 225 Fg(-1) at a current density of 2 Ag-1 and its capacitance decreased to 78 % of its initial value after 3,000 cycles.