Even though the international trade system was originally developed without considering environmental protection, efforts are being made to join environmental and political aims. In Mexico, Baja California Sur (BCS) is the most arid state and that with the longest coastline. Efforts to insert BCS into the international market have usually reflected the environmental topic. The purpose of this work was to identify environmental, economic and social impacts caused by the North American Free Trade Agreement (NAFTA) in BCS. We analysed, from 1994 to the present, the main fishery companies for growth in production, increases in the quantities and value of export products, the participation of personnel in environmental aspects, changes in pollution prevention and control, new technology, increase of investments and generation of employment. We find that in the short and medium term, NAFTA in the fishery sector has had no significant effects on the environmental, economic and social variables studied. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment