  We have searched for the tau lepton flavor violating decays tau- -> l-K0s (l
= e or mu), using a data sample of 281 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- -> e-K0s) < 5.6 * 10^-8 and B(tau- -> m^-K0s) < 4.9
* 10^-8 at the 90% confidence level. These results are improvements by factors
of 16 and 19, respectively, compared with previously published limits from
CLEO.
