Radiative corrections to top quark decay into charged Higgs at the Tevatron

We present the computation of the leading one-loop electroweak radiative corrections to the non-standard top quark decay width Gamma(t->H+ b), using a physically motivated definition of tan(beta). We find that the corrections are large, both in the Minimal Supersymmetric Standard Model (MSSM) and the Two-Higgs-Doublet Model (2HDM). These corrections have an important effect on the interpretation of the Tevatron data, leading to the non-existence of a model-independent bound in the tan(beta)-MH+ plane.