We have searched in ppbar collisions at sqrt s = 1.8 TeV for events with three charged leptons and missing transverse energy. In the Minimal Supersymmetric Standard Model, we expect trilepton events from chargino-neutralino (chi\bar~^+\- _1 chi\bar~^0_2) pair production, with subsequent decay into leptons. We observe no candidate e^+ e^- e^+\-, e^+ e^- mu^+\-, e^+\- mu^+ mu^- or mu^+ mu^- mu^+\- events in 106 pb^-1 integrated luminosity. We present limits on the sum of the branching ratios times cross section for the four channels: sigma_chi\bar~^+\-_1 chi\bar~^0_2 -> 3l + X) < 0.34 pb, M_chi\bar~^+\-_1 > 81.5 GeV/c^2 and M_chi\bar~^0_2 > 82.2 GeV/c^2 for tan beta = 2, mu = -600 GeV/c^2 and M_q\bar~ = M_g\bar~.