  We present results for the confinement-deconfinement interface tension
$\sigma_{cd}$ of quenched QCD. They were obtained by applying Binder's
histogram method to lattices of size $L^2\times L_z\times L_t$ for $L_t=2$ and
$L=8,10,12\mbox{ and }14$ and various $L_z\in [L,\, 4\, L]$. The use of a
multicanonical algorithm and rectangular geometries have turned out to be
crucial for the numerical studies. We also give an estimate for $\sigma_{cd}$
at $L_t=4$ using published data.
