This article reconstructs the life story of a commodity, the blue jean, in 1960s and 1970s Buenos Aires. It analyzes how the blue jean was commercialized, who wore it, and the meanings they attributed to the jeans. In addition, it explores the cultural representations of the blue jean and analyzes the debates it sparked in the public arena, which revolved around the "Americanization" of Argentina's culture; the shifting understandings of gender and sexuality; and the changing youth identities the blue jean allegedly embodied. In 1960s and 1970s Argentina, the blue jean acted as a prime marker of a youth identity as separate and eventually opposed to an "adult" identity and fashion. Jeans were the first dress item to be worn exclusively by young men and women, who increasingly dressed—and thought, and behaved—differently from the older generation. Yet the blue jean also served to signal and reinforce class distinctions and gender differences among young people. Jean styles, brands, and "nationalities"—whether imports or locally produced—became ways of elaborating intra-generational differences. By the mid 1970s, there was a "blue-jean generation," although young people neither wore the same jeans nor endowed them with the same meanings.