The main aim of this paper is to examine how the recent themata developments in Social Representations Theory can be linked with the classical process involved in the construction of social representations—anchoring—, as well as with the communicative modalities that are part of the theory since its inception. This was done through a study of the representation of GMOs in the Portuguese press, taken as an opportunity for addressing the issues related to the role played by old categories in rendering (...) new meanings and in establishing new categories.A further objective of the study, more applied in nature, was to explore whether the central characteristics of the representations of biotechnology in European countries were also present in Portugal.All articles that included the expressions Genetically Modified/Genetic Modification/Manipulation or Transgenics, were collected, in five Portuguese newspapers, during the years of 1999, 2000 and 2001. Content analysis of the 239 articles collected showed that their thematical organisation re-constitutes the Red/Green dichotomy found in most European countries. The Red/health discussion is structured around such themata as health/disease, risk/safety, benefits/problems, and anchors in categories like science and progress. The nature/culture opposition emerges, in turn, in the Green/food discussion, which anchors on categories like ideology and employs Propaganda as a communicative modality—a set of indicators configuring a more polemic debate. The conclusions discuss the relevance of linking themata with anchoring and the importance of devising more fine-grained tools for the analysis of Diffusion. (shrink)