This paper discusses the effects of the real exchange rate (RER, defined as the price of the foreign currency in units of the domestic currency, adjusted by price levels) on the diversification and technological intensity of the export structure. Based on a North-South Ricardian model of trade with a continuum of goods, in which comparative advantage depends on the RER and leads and lags in innovation and diffusion of technology, two hypotheses are suggested and tested. The first one is that a higher RER allows for a higher diversification of exports. The second hypothesis is that this diversification implies an upgrading in the technological intensity of exports. We find favorable evidence for the two hypotheses from a panel data study, including 111 counties in the period 1962-2008. These results suggest that a competitive RER should be considered a relevant variable in the process of economic development as it encourages the transformation of the pattern of specialization. © 2013 Copyright Taylor and Francis Group, LLC.