  sing a theorem dubbed the {\em Multibreather Stabiliy Theorem} [Physica D 180
(2003) 235-255] we have obtained the stability properties of multibreathers in
systems of coupled oscillators with on-site potentials, with an inhomogeneity.
Analytical results are obtained for 2-site, 3-site breathers, multibreathers,
phonobreathers and dark breathers. The inhomogeneity is considered both at the
on-site potential and at the coupling terms. All the results have been checked
numerically with excellent agreement. The main conclusion is that the
introduction of a impurity does not alter the stability properties.
