Various manganese oxides nanoparticles can be synthesized using a versatile electrochemical method. In this method, KMnO4 solution was electrolyzed using carbon electrodes at 60 degrees C. By only adjusting the solution pH, the nanoparticles obtained can be alpha-MnO2 or Mn2O3. In acid solution (pH similar to 4), the particles produced were alpha-MnO2. On the other hand, in basic solution (pH similar to 9), the particles produced were Mn2O3. Both alpha-MnO2 and Mn2O3 particles are nearly spherical in shape with surface area ranging from 71-157 m(2)/g and diameter 1579-188 nm. The surface area and diameter are influenced by the voltage during electrolysis. The higher the voltage, the larger the diameter particles are.