Branding decisions are becoming increasingly important in services, but little service-specific research has focused on this domain so far. This is surprising, as the service industry accounts for an ever-growing share of the global economy, whereas service aspects have become increasingly important for all goods. Marketing managers may want to capitalize on previously acquired brand equity by extending a reputable brand to a new category. Little is known, however, about the extent to which consumer-based brand equity transfers to unrelated categories in a services context. A study replicates Aaker and Keller's (1990) study and extends it to the services domain. A data set provides evidence that in a services context, consumers use complementarity to the original category as a major cue to evaluate extensions. As a consequence, brand extension strategies could probably be used most successfully in cases where a significant similarity in service delivery processes exists.