Limits on the tau neutrino mass from collider experiments

The origin of neutrino masses is one of the most puzzling questions of present day particle physics. Although cosmological arguments suggest the masses of stable neutrinos to be smaller than few eVs, unstable tau neutrinos can evade cosmological bounds up to the MeV mass scale. Evidence for such heavy neutrinos could be found in the kinematical reconstruction of two body decays of T's produced by e(+)e(-) colliders. The experimental techniques, results and short-term expectations of the most performing experiments are reviewed and discussed.