The present article aims to show that collective memories could serve as a criterion in social categorization. We predicted that a target person who shares common collective memories will be perceived as similar (to the self), relatively more favorably and categorized as an ingroup member. We conducted four studies using memories of historical events or childhood objects. These studies consistently showed that a target who shares common memories is more likely to be perceived as an ingroup member than someone who does not. This effect is mediated by perceived similarity to the self. Finally, individuals who share common memories are perceived more favorably than when they do not. However, according to the type of collective memories (historical events vs. childhood memories) sharing memories impacts either perceived competence or perceived warmth. The current sets of studies support the idea that collective memory influences social categorization processes, exemplifying its group identity-defining function.