This paper has been prepared at the request of UNESCO (Venice and Moscow Offices) and the International Council for Science (ICSU) to provide input for discussions at the Conference of the Academies of Sciences of Eastern and South Eastern Europe on the theme “Global Science and National Policies: the Role of Academies”, that took place in Chisinau, Republic of Moldova, on 4 and 5 May 2007, by the Moldovan Academy of Sciences. The paper focuses on the role of Academies of Sciences, both in relation to science and the science community and in relation to society and (governmental) decision-makers. However, its focus is not restricted to the external functions of Academies, but it also considers some internal organizational aspects: given the external functions of an Academy, what is – generally – required in terms of organization and infrastructure for an Academy to realize these functions effectively and efficiently?