The 2nd International Symposium on Hydrotreatment and Hydrocracking of Oil Fractions, which is also the 7th in the series of European Workshops on Hydrotreatment, took place in Antwerpen, Belgium from November 14 to 17. The Symposium emphasized how oil refining faces increasingly severe environmental regulations. These and the increasing application of heavier crudes containing more S-, N- and metal components call for more efficient hydrotreatment and hydrocracking processes. It is clear from the keynote lectures, the oral contributions and the posters of this meeting that adapting the operating conditions will not suffice. Adequate catalysts need to be developed, with different composition and structure. Surface science techniques and molecular modeling are now well established tools for such a development. They should be of help in widely different aspects, like the role of precursors in the preparation or the modifications undergone by the catalyst under reaction conditions. The improvement of hydrotreatment and hydrocracking also needs accurate modeling of the chemical reactor. This requires more representative hydrodynamics and kinetic models whose validity extends to the very low S- and N-contents. These areas should be vigorously developed.