We generalize the entropy function formalism to five-dimensional and
four-dimensional non-extremal black holes in string theory. In the near horizon
limit, these black holes have BTZ metric as part of the spacetime geometry. It
is shown that the entropy function formalism also works very well for these
non-extremal black holes and it can reproduce the Bekenstein-Hawking entropy of
these black holes in ten dimensions and lower dimensions.Comment: 19 pages, no figure, JHEP3 style, to appear in JHE
