We present the fabrication and room temperature operation of single electron transistors using 8nm8nmtungsten islands deposited by focused ion beamdeposition technique. The tunnel junctions are fabricated using oxidation of tungsten in peracetic acid. Clear Coulomb oscillations, showing charging and discharging of the nanoislands, are seen at room temperature. The device consists of an array of tunnel junctions; the tunnel resistance of individual tunnel junction of the device is calculated to be as high as 25.13GΩ25.13GΩ. The effective capacitance of the array of tunnel junctions was found to be 0.499aF0.499aF, giving a charging energy of 160.6meV160.6meV.