The globalization of the agri-food system has triggered a series of transnational migratory flows. The most widely studied ones have involved seasonal day laborers, who perform the most arduous, precarious and seasonal work. Transnational workers specializing in both in the field and the various activities required for a globalized wine industry have not been studied. This article examines a network of specialized agricultural workers: grafters. The origin of the network in Napa County and its expansion and consolidation which have taken these workers to different countries and continents is studied. The characteristics of this network and the social and labor trajectories of these Mexican grafters are analyzed, as well as their importance in an industry based on an economy of signs and spaces, where the quality and distinction of their wines is a central element that has led to a growing need for this activity.