  I present two disparate examples of isospin violation in hadronic B-decays.
In the first, the presence of \rho^0-\omega mixing in the decay
B^\mp\to\rho^\mp\rho^0(\omega)\to\rho^\mp\pi^+ \pi^- permits the extraction of
sgn(\sin \alpha), where \alpha is the usual angle of the unitarity triangle,
with minimal hadronic uncertainty. In the second, the presence of
\pi^0-\eta,\eta' mixing can obscure the extraction of \sin 2\alpha from an
isospin analysis in B\to\pi\pi decays.
