Using 2.0fb-1 of integrated luminosity collected by the CDFII
experiment at the Tevatron ppbar collider at root(s)=1.96TeV,
we present a search for supersymmetry using the three lepton and
missing energy signature of chargino-neutralino production.
We expect to see about 12 supersymmetric events for a suitable
choice of parameters in the mSUGRA model.  Our observation of seven
events is consistent with the Standard Model expectation of 6.4+-1.1
events.  We rule out chargino masses below 141GeV/c2 in
certain mSUGRA regions and also present results in a model-independendent
fashion.