  We compute the one-loop radiative corrections to the masses of the top quark,
the stop squarks and the gluino in the Minimal Supersymmetric Standard Model.
We include the loops controlled by the strong coupling constant and the top
Yukawa coupling, neglecting those controlled by the $SU(2) \times U(1)$ gauge
couplings and by other Yukawa couplings. We find that the significant
scale-dependence of the renormalization-group-improved tree-level expressions
is almost completely removed. Even for natural choices of the renormalization
scale, corrections can be numerically relevant. Our results should allow more
reliable predictions to be extracted from candidate fundamental theories beyond
the MSSM.
