Language planning and policy in Catalonia has been a focus of much interest and discussion over the past three decades. This article goes beyond issues of policy in order to examine what happens when an influential constituency in the linguistic landscape of Catalonia, namely advertisers, have a “free choice” as regards the language(s) which they use when advertising in a key site in the print media, that of El Periódico de Catalunya, one of the two biggest-selling newspapers in Catalonia. Uniquely this paper publishes daily “identical” versions in Castilian Spanish and in Catalan and this feature obliges advertisers to select from several sociolinguistic options as regards the language(s) in which their advertising is published. The article tries to establish whether any patterns of language choice appeared to dominate in this advertising and to identify any links which might exist between the characteristics of the companies concerned, the types of products and services on offer and the linguistic choices made. The results of the study suggest that there is a tendency among many advertisers, particularly those of certain types of products which cross national boundaries and are associated with technological development and “modernity,” to use Castilian in both the Castilian and the Catalan versions of the newspaper.