Based on recent evidence for individual differences in stereotype activation, we claim that the impact of social categories in impression formation is moderated by individual differences in the strength of associations between a social category and stereotypical content. In Experiment 1 and 2, participants with strong stereotypical associations (measured with an Implicit Association Test, Greenwald, McGhee, & Schwartz, 1998) based their impressions on category as well as on individuating information. In contrast, participants with weak associations based their impressions only on individuating but not on category information. Employing a multinomial model for the "Who-said-what?" paradigm (Klauer & Wegener, 1998), Experiment 3 demonstrated that these effects are due to increased stereotyping and decreased individuation for perceivers with strong stereotypic associations compared to those with weak associations, rather than to individual differences in categorization.