The Determinants of Export Performance: A Firm-Level Study of Italian Manufacturing. - This paper analyzes some determinants of a firm's probability of exporting and export intensity and presents the findings of an empirical study carried out on a large sample of Italian firms. On the basis of Probit and Tobit estimates, it emerges that these determinants change according to the size of firms. In particular, only for small firms is the relationship between size and export performance positive. The export activity of small and medium-sized firms decreases with the share of sales due to subcontracting. Larger firms, instead, benefit more from being affiliated with business groups and performing innovative activities of a different nature. JEL no. F10, D21, O33.