  We present a detailed analysis of the thermodynamics of exact asymptotically
flat hairy black holes in Einstein-Maxwell-dilaton theory. We compute the
regularized action, quasilocal stress tensor, and conserved charges by using a
`counterterm method' similar to the one extensively used in the AdS-CFT
duality. In the presence of a non-trivial dilaton potential that vanishes at
the boundary we prove that, for some range of parameters, there exist
thermodynamically stable black holes in the grand canonical and canonical
ensembles. To the best of our knowledge, this is the first example of a
thermodynamically stable asymptotically flat black hole, without imposing
artificial conditions corresponding to embedding in a finite box.
