The report examines the export performance of Mexican enterprises in the 1990s, to determine whether the intended effects of trade liberalization, have indeed occurred. The depth, and extent of changes in outward orientation of firms are explored, as well as the characteristics of firms that became more export-oriented. Further analysis focus on the degree of linkage between the export sector, and domestic economy, or conversely, the extent to which the export sector is an "enclave", whose behavior is independent from the rest of the economy. The factors that determine export behavior, and the extent to which exporting is "permanent" vs. "transitory" are reviewed, together with the extent to which productivity gains from exporting have been realized, whether through learning by direct exporters, or through spillovers to indirect exporters, and others. The report relies on statistical analysis of cross-section/time-series databases, with observations at the level of the individual plant, or firm, which led to the annual industrial survey (1993-98), the monthly census of plants under the "maquila" regime (1990-98), and, the Central Bank customs database of export/import at the firm level (1991-98). Conclusions suggest that while exporters have higher productivity rates, profitability is equal compared to non-exporters, but inventory turnover tends to be higher for non-exporters, possibly explained by higher re-stocking costs for exporters.