We obtain the induced Lorentz- and CPT-violating term in QED at finite temp
erature using the imaginary-time formalism and dimensional regularization.
Its form resembles a Chem-Simons-like structure, but, unexpectedly, it does
not depend on the temporal component of the fixed b(mu) constant vector th
at is coupled to the axial-vector current. Nevertheless, Ward identities ar
e respected and its coefficient vanishes at T = 0, consistent with previous
computations with the same regularization procedure, and it is a nontrivia
l function of temperature. We argue that at finite T a Chern-Simons-like Lo
rentz- and CPT-violating term is generically present, the value of its coef
ficient being unambiguously determined up to a T-independent constant, rela
ted to the zero-temperature renormalization conditions.