Résumé : The objective of this paper is to provide an in-depth analysis of the patenting performances of six Belgian universities over the period 1985-1999. Beside the evolution of the number of patent families, we provide insights about the potential value of these patents (through forward patent citations analysis), about the institutional sources of the knowledge (through non patent citations and backward patent citations), about their international patenting strategy, and the type of co-assignee. The results show that KUL is by far the most productive university in Belgium (both in terms of the number of patent applications and the number of forward citations per patent). This is due to a size effect, a longer history of patenting academic inventions, to a focus on bio-tech patents and to a very productive collaboration with the Institute of Organic Chemistry of the Academy of Sciences of the Czech Republic. There is however a clear indication that a catching up process by other universities is taking place, in terms of both the quantity of patent applications and their quality.