We were interested in deepening the knowledge about the history of the working class in Patagonia, Argentina, and in Chubut’s North-East in particular. In this region, since the 1960s, industrialization was stimulated and subsidized by the national and provincial state, which gave origin to Trelew’s Industrial Textile Park and to the primary aluminium production plant ALUAR, in Puerto Madryn. Through these years a new working class was formed in the region, resulting from the massive arrival of different kinds of migrants from other provinces of the country, from the rural zones of the province of Chubut and from neighbouring Chile. This extremely heterogeneous working class, that in many cases had no previous experience of industrial work, union activity or urban life, met a social context of full employment, frequent inauguration of new factories and the possibility to improve its living conditions and better work conditions. We’ve tried to understand how this working class was formed, how it developed its first actions and organization and in what conditions they faced the changes that began around the middle of the 1980s and fully impacted it during the 1990s.