QCD corrections to the decay H+->t(b)over-bar in the minimal supersymmetric standard model

We present a complete calculation of the Omicron(alpha(s)) QCD corrections to the width of the decay H+ --> <t (b) over bar> within the Minimal Supersymmetric Standard Model. We find that the QCD corrections are quite important, and that the supersymmetric QCD corrections (due to gluino, <(t) over tilde> and <(b) over tilde> exchange) can be comparable to or even larger than the standard QCD corrections in a large region of the supersymmetric parameter space. This is mainly due to the effect of large left-right mixings of stop (<(t) over tilde>) and sbottom (<(b) over tilde>). This could significantly affect the phenomenology of the H+ search.