  The effect of quenched disorder on the underdamped motion of a periodically
driven particle on a ratchet potential is studied. As a consequence of
disorder, current reversal and chaotic diffusion may take place on regular
trajectories. On the other hand, on some chaotic trajectories disorder induces
regular motion.
  A localization effect similar to {\sl Golosov Phenomenon} sets in whenever a
disorder threshold that depends on the mass of the particle is reached.
Possible applications of the localization phenomenon are discussed.
