Kentucky Governor Ernie Fletcher signed an executive order Tuesday banning smoking in all state office buildings and enclosed structures.
Fletcher says the move is intended to protect the health of non-smokers who might be exposed to second hand smoke.
Fletcher is a physician.
Government Relations Director Shannon Pratt of the American Cancer Society in Kentucky called the move "monumental."
Fletcher says the ban will extend to state buildings controlled by the executive branch.
That would exclude portions of the state Capitol and the Capitol Annex that are under the control of the legislative branch.
Most state office buildings currently have designated smoking rooms.
When the ban takes effect, smoking will be permitting only in designated outdoor smoking areas.