Abstract: In this paper, an index of the depth of experience with state-level institutions, or state antiquity, is derived for a large set of countries. We show that state antiquity is significantly correlated with measures of political stability and institutional quality, with income per capita, and with the rate of economic growth between 1960 and 1995. State antiquity contributes significantly to the explanation of differences in growth rates, explaining half of the differences in growth rates between countries like China and Mauritania, which are located at the two ends of the spectrum. It is also a good instrument for \"social infrastructure,\" which explains cross-country differences in worker productivity. Copyright 2002 by Kluwer Academic Publishers