This study aims to describe and explain the impact of trade liberalization between the EU-15 and the southern Mediterranean countries, with special emphasis on Southern EU (Portugal, Spain, France, Italy and Greece). The selected activity to be studied is the processing tomato industry. To do that, we use three related approaches (systems, industrial economics and management tools). After describing the tomato processing system, we introduce three case studies : Copador (member of CIO) located in Parma, Louis Martin SA nearby Avignon and Alsat SL located in Don Benito (Extremadura). Some conclusions : the EU processing tomato industry will continue and probably expand its activities on the Mediterranean borders ; the competition between Italy and Spain will increase ; the southern part of France risks losing its first-level processing activities ; specialization of work within the European space will intensify, with the southern part specializing in raw materials and the northern part in high value added products ; Greek and Portuguese activities will carry on. Three main reasons can be advanced : the raw materials have to meet some very rigorous standards ; some activities (manufacturing of tomato paste) are highly mechanized and, second and third level finished products which are evolving very quickly (packaging, recipes and process techniques) require good logistics and flexible services.