  We have searched for tau lepton decays, tau- -> Lambda-bar pi- and tau- ->
Lambda pi-, that simultaneously violate the conservation of the lepton and
baryon number using a data sample of 154 fb^{-1} collected with the Belle
detector at the KEKB e+e- asymmetric-energy collider. No evidence for a signal
was found in either of the decay modes and we set the following upper limits
for the branching fractions: B(tau^- -> Lambda-bar\pi-) < 1.4 * 10^{-7} and
B(tau^- -> Lambda pi^-) < 0.72 * 10^{-7} at the 90% confidence level. This is
the first search ever performed for these modes.
