Electronic Journal of Differential Equations, Vol. 2008(2008), No. 09, pp. 1-10. Title: Maslov index for Hamiltonian systems Author: Alessandro Portaluri (Univ. di Milano-Bicocca, Italy) Abstract: The aim of this article is to give an explicit formula for computing the Maslov index of the fundamental solutions of linear autonomous Hamiltonian systems in terms of the Conley-Zehnder index and the map time one flow. Submitted September 10, 2007. Published January 17, 2008. Math Subject Classifications: 53D12, 37J05. Key Words: Maslov index; Kashiwara index; Hamiltonian systems. An addendum was posted on July 19, 2008. It clarifies the contribution of this article in relation to three new references. Please see the last page of this manuscript.