  This paper deals with the dynamics of a simple family of holomorphic
diffeomorphisms of $\C^2$: the polynomial automorphisms. This family of maps
has been studied by a number of authors. We refer to [BLS] for a general
introduction to this class of dynamical systems. An interesting object from the
point of view of potential theory is the equilibrium measure $\mu$ of the set
$K$ of points with bounded orbits. In [BLS] $\mu$ is also characterized
dynamically as the unique measure of maximal entropy. Thus $\mu$ is also an
equilibrium measure from the point of view of the thermodynamical formalism. In
the present paper we give another dynamical interpretation of $\mu$ as the
limit distribution of the periodic points of $f$.
