Purpose ? The purpose of this paper is to provide insight into whether GM-labelling leads to different processing behaviour of food stimuli compared to when products are not labelled. Design/methodology/approach ? A task was designed to investigate people's categorization behaviour as a function of information provided. In two studies each participant was randomly allocated to either the experimental 'GM-labelled condition', or the control 'non-labelled condition'. Findings ? Different processing strategies and different characteristics are used to judge products that are labelled as genetically modified or not. GM labelling of foods is interpreted to induce analytical processing of information and therefore the products are classified relatively more often on the basis of verifiable categorization criteria compared to when they were not labelled as GM. When products are not labelled as GM, information is more likely to be automatically processed and non-verifiable categorization criteria are used. Originality/value ? This is the first study to examine the processes that labelling as GM brings about.