Uncertainties on the measurements of the top mass at a future E+E- collider

The uncertainties due to limited knowledge of the multi-hadron final state on the measurements of the top mass at future linear colliders are discussed. The study is performed for E+E- -> tt-bar annihilation events at the centre-of-mass energy of 500 GeV using Monte Carlo models tuned to LEP experiments. The uncertainties are determined for the all hadronic top-decay mode as well as for the lepton-plus-jets channel.