  We study the supersymmetric (SUSY) QCD radiative corrections, at the one-loop
level, to $h^0$, $H^{\pm}$ and t quark decays, in the context of the Minimal
Supersymmetric Standard Model (MSSM) and in the decoupling limit. The
decoupling behaviour of the various MSSM sectors is analyzed in some special
cases, where some or all of the SUSY mass parameters become large as compared
to the electroweak scale. We show that in the decoupling limit of both large
SUSY mass parameters and large CP-odd Higgs mass, the $\Gamma (h^0\to b \bar
b)$ decay width approaches its Standard Model value at one loop, with the onset
of decoupling being delayed for large $\tan\beta$ values. However, this
decoupling does not occur if just the SUSY mass parameters are taken large. A
similar interesting non-decoupling behaviour, also enhanced by $\tan\beta$, is
found in the SUSY-QCD corrections to the $\Gamma (H^+\to t \bar b)$ decay width
at one loop. In contrast, the SUSY-QCD corrections in the $\Gamma (t\to W^+ b)$
decay width do decouple and this decoupling is fast.
