Polyaniline/poly(vinyl alcohol)/ruthenium oxide (RuO2) composite nanofibers were produced by electrospinning technique. Hydrous ruthenium chloride was used as a precursor at different concentrations, and the samples were annealed at 200 degrees C. The morphology of the nanofibers was investigated by scanning electron microscopy. The average diameter of the produced nanofibers is between 200 and 300 nm. Fourier transform infrared spectroscopy and Raman spectroscopy were used for the investigation of the vibration modes and structure of the samples. Differential scanning calorimeter, and thermal gravimetric analysis up to 400 degrees C revealed the crystallinity degree and thermal stability of the samples. Impedance spectroscopy for the samples with capacitor structure was conducted as function of RuO2 concentration and temperature. The tests revealed the decrease of electrical resistivity and activation energy with increasing RuO2 concentration for the as-prepared samples, while the annealed samples showed lower activation energy values of similar to 0.1 eV with increasing the concentration of RuO2. The electrical properties of the fabricated composite nanofibers could be controlled that make them suitable to be utilized in devices for energy storage applications.