Like many countries, Sri Lanka has used Export Processing Zones as a means of promoting manufactured exports. This article uses a cost-benefit approach to estimate the returns to the national economy from the main zones. Overall, the zones are found to be economically efficient with an economic rate of return of 23 per cent. The zones are dominated by textile and clothing firms, however, and returns in other sectors are considerably lower. Unlike zones elsewhere, profits to local investors are a significant part of national benefits.