QCD Corrections to $t\overline{b}H^{-}$ Associated Production in $e^{+}e^{-}$ Annihilation

We calculate the QCD corrections to the cross section of e^+ e^- -> t anti-b H^- and its charge-conjugate counterpart within the minimal supersymmetric extension of the Standard Model. This process is particularly important if m_t < m_H + m_b and root(s) < 2 m_H, so that t -> b H^+ and e^+ e^- -> H^+ H^- are not allowed kinematically. Depending on tan(beta) and m_H, the corrections can be of either sign. For large tan(beta), they lead to a dramatic reduction of the cross section, by more than 50%.