In order to understand Uruguay’s long-run economic evolution it becomes crucial to interpret its export performance during the First Globalization. The lack of accuracy of official figures, especially official prices used, calls for an adjustment of Uruguayan export series. We have used empirical evidence to test the accuracy of quantities and values of export records, first, according to import partners’ records and, second, according to international market prices. Results show a general undervaluation of official export values during the period along with severe distortions in the registers caused by transit trade. We reconstructed new Uruguayan export f.o.b values and an export price index which present a more unstable and less dynamic export evolution than that of neighbouring Argentina.