Signatures of Supersymmetry at B-Factories

We discuss CP asymmetries in $B^0$-meson decays and \BsBs mixing within the framework of the supersymmetric standard model (SSM). It is shown that \BdBd and \KK mixings could receive sizable new contributions through box diagrams mediated by the charginos and charged Higgs bosons. This implies that the CP-violating phase of the Cabibbo-Kobayashi-Maskawa matrix may have a value which is different from the one predicted by the standard model (SM). The value of the CP-violating phase affects the amounts of the CP asymmetries and \BsBs mixing. We examine predictions for these quantities in both the SSM and the SM, exploring the difference between the two models.