  We study the angular distribution of the charged lepton in the top-quark
decay into a bottom quark and a W boson which subsequently decays into
\ell\nu_{\ell}, when a hard gluon is radiated off. The absorptive part of the t
\to bWg decay amplitudes, which gives rise to T-odd asymmetries in the
distribution, is calculated at the one-loop level in perturbative QCD. The
asymmetries at a few percent level are predicted, which may be observable at
future colliders.
