The Zoological Museum of the Liège University presents the animal kingdom diversity in his public showrooms, open since 1962, but it shelters also a great mass of specimens conserved in depositories and ignored. These specimens are almost all identified, registered with an inventory number and systematically arranged. The information kept in old registers since 1837 is now available on computer (Filemaker Pro database). The scientific names are updated as well as possible, and we compare now the theoretical data with the real material found in the different stocking areas. This step of the collection management allows us to find some unregistered or unidentified pieces, coming from various places of the world. From the Belgian fauna point of view, the marine material collected in the 1880s by Edouard VAN BENEDEN off the Belgian coast near Ostend has not been completely exploited. These old specimens of crustaceans and tunicates reflect the biodiversity of the Belgian marine fauna at that time, and they should be used in the comparative studies about fauna evolution. Tunicates are well represented, with several types described by VAN BENEDEN, JULIN, DAMAS, etc. Concerning the freshwater fauna, the collections have got for example a lot of crustacean branchiopods, whose study has revealed the presence of a new species in Belgium, and enabled us to complete our knowledge of the past distribution of these animals in our country and in some important foreign sites. Concerning the terrestrial fauna, we mention the innumerable insects, underestimated, and of which only some taxa have been reviewed, and numerous birds, reptiles, fishes, etc. The richness of a collection depends on the nature of his specimens rather than their number. His scientific appraisal depends on the number of researchers who are interested in it. The zoological collections of the University of Liege are worth a scientific exploitation and are only waiting for the visit of scientific contributors.