  In supersymmetric theories, the decays of the neutral CP-even and CP-odd as
well as the charged Higgs bosons into scalar quarks, in particular into top and
bottom squarks, can be dominant if they are kinematically allowed. We calculate
the QCD corrections to these decay modes in the minimal supersymmetric
extension of the Standard Model, including all quark mass terms and squark
mixing. These corrections turn out to be rather large, altering the decay
widths by an amount which can be larger than 50%. The corrections can be either
positive or negative, and depend strongly on the mass of the gluino. We also
discuss the QCD corrections to the decays of heavy scalar quarks into light
scalar quarks and Higgs bosons.
