Supersymmetry, if realized in Nature, predicts the existence of
new particles, as chargino and neutralino, which might manifest themselves
with peculiar signatures. Three leptons and large missing transverse energy
in the event could signal their associated production. We report the latest
results of the search performed by the CDF Collaboration in s**(1/2) = 1.96
GeV/c2 proton-antiproton collisions at Tevatron Run II.