In the spring of 1954, from April 28 to June 14, six members of the scientific staff of the Zoological Museum of Amsterdam made a collecting trip to Yugoslavia. The primary purpose of this journey was collecting for the Museum, animals from that part of Europe being only poorly represented. At the same time, it was the intention to collect large series at as many localities as possible for the study of geographical variation. Collecting activities were restricted to certain animal groups, according to the personal interest and collecting experience of the participants. Therefore, the collections chiefly consist of invertebrates: (Macro) Lepidoptera, Arachnoidea, Isopoda, Mollusca, and aquatic microfauna (Copepoda, Amphipoda, Nematoda, Hydrachnidae, Halacaridae). The results of the expedition will be published under the collective title “Zoological results of a collecting journey to Yugoslavia, 1954”, and will appear successively in Beaufortia.