  We discuss the physics potential of future tritium beta-decay experiments
having a sensitivity to a neutrino mass ~\sqrt{|\Delta m^{2}_{23}|}~5x10^{-2}
eV. The case of three-neutrino mixing is analised. A negative result of such an
experiment would imply that the neutrino mass spectrum is of normal
hierarchical type. The interpretation of a positive result would depend on the
value of the lightest neutrino mass; if the lightest neutrino mass satisfies
the inequality min(m_j) << \sqrt{|\Delta m^{2}_{23}|}, it would imply that the
neutrino mass spectrum is of the inverted hierarchical type.
