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Rocks of the Campanian/Maastrichtian transition form the main bulk of the Duwi Formation, exposed in the Nile Valley, Southern Egypt. In terms of biostratigraphy, the concerned transition has been subdivided into three planktic foraminiferal zones coeval with two ammonite and three bivalve zones. The proposed zones have been integrated and correlated with other zonal schemes. The Campanian/Maastrichtian boundary has been located at the contact between the Campanian Bostrychoceras polyplocum and the Maastrichtian Pachydiscus neubergicus Ammonite Zones, corresponding with the contact between the Campanian Globotruncana aegyptiaca and the Maastrichtian Rugoglobigerina hexacamerata planktic foraminiferal zones, as well as the contact between the Campanian Cameleolopha tissoti-Plicatula pausicostata and the Maastrichtian Abruptalopha abrupta bivalve zones. (C) 2004 Elsevier Ltd. All rights reserved.