Semantic interference in word retrieval has been observed for both well-learned and ad hoc inter-item relations. We tested whether such semantic interference extends to the blocked cyclic naming of racially homogeneous vs. heterogeneous faces. No information except arbitrarily assigned names was provided for novel faces. Yet we observed interference in naming individuals in homogeneous groups. Moreover, consistent with other findings in the social domain, interference occurred for other-race but not for own-race faces. Because this interference effect does not require a rich knowledge base about individuals, it is consistent with the view that interference arises in adjustments to the strength of conceptual-lexical links rather than in knowledge structures themselves. Evidence of modulation by target race further suggests that interference effects may provide an effective tool for exploration of social categorization processes.