Why does it seem unlikely that retirees should be political activists? What does that reaction say about our understandings of retirement and of activism? This article examines the experience of a group of older activists who, among other things, rally weekly in front of the National Congress in Buenos Aires, Argentina, and have done so for more than two decades. Regardless of advanced age and infirmity, these men and women, some in their eighties and nineties, refuse to be defined as passive by their roles as retirees and grandparents. After examining some of the tensions embodied in the idea of activist pensioners, this article proceeds to look at the pensioners’ own understandings of where their activism comes from and what sustains it. Situating the pensioners’ struggle in broader historical processes in Argentina illuminates their motives and strategies. The article thus also demonstrates that a historical approach provides a productive strategy for analysing elder social movements.