  We obtain the induced Lorentz- and CPT-violating term in QED at finite
temperature using imaginary-time formalism and dimensional regularization. Its
form resembles a Chern-Simons-like structure, but, unexpectedly, it does not
depend on the temporal component of the fixed $b_\mu$ constant vector that is
coupled to the axial current. Nevertheless Ward identities are respected and
its coefficient vanishes at T=0, consistently with previous computations with
the same regularization procedure, and it is a non-trivial function of
temperature. We argue that at finite $T$ a Chern-Simons-like Lorentz- and
CPT-violating term is generically present, the value of its coefficient being
unambiguously determined up to a $T-$independent constant, related to the
zero-temperature renormalization conditions.
