Upper Campanian Belemnitella and Lower Maastrichtian Belemnella and Belemnitella faunas from the chalks of the Mons Basin in Belgium are described, utilizing univariate and bivariate biométrie analyses. The Upper Campanian belemnite faunas comprise six taxa of Belemnitella, including two left in open nomenclature: B. mucronata, B. woodi, B. minor I, B. minor II, B . sp. 1 and B . sp. 2. The lower Lower Maastrichtian fauna includes Belemnella (Pachybelemnella) obtusa with subordinate Belemnitella minor II and belemnitella pulchra . The Upper Campanian and Lower Maastrichtian lithostratigraphical formations are placed in the international stratigraphical framework on the basis of the belemnite faunas. The Upper Campanian chalks are subdivided into four Belemnitella zones, and these are in ascending order: the lower Upper Campanian B. mucronata Zone below and B. woodi Zone above, in addition to the upper Upper Campanian B. minor I Zone below and B. minor II Zone above. These zones are proposed as formal zones, because they have been recognized in widely spaced areas in northwest Europe. The Craie Phosphatée de Ciply is placed in the Belemnella obtusa/Belemnitella minor II Zone, which is from the upper part of the lower Lower Maastrichtian.