We conducted three experiments to study the role of instrumental (e.g. knife–bread) and categorical (e.g. cake–bread) relations in the development of conceptual organization with a priming paradigm, by varying the nature of the task (naming – Experiment 1 – or categorical decision – Experiments 2 and 3). The participants were 5-, 7- and 9-year-old children and adults. The results showed that on both types of task, adults and 9-year-old children presented instrumental and categorical priming effects, whereas 5-year-old children presented mainly instrumental priming effects, with categorical effects remaining marginal. Moreover, the magnitude of the instrumental priming effects decreased with age. Finally, the priming effects observed for 7-year-old children depended on the task, especially for the categorical effects. The theoretical implications of these results for our understanding of conceptual reorganization from 5 to 9 years of age are discussed.