Three levels including Anisian (probably Pelsonian) benthonic Foraminifera [Hoyenella gr. sinensis (Ho)),Pilamminella grandis (Salaj)), Pilammina aff. densa Pantic,, etc.] have, been identified in the transgressive systems tracts of two depositional sequences (Muschelkalk) of the Weser Basin (Diemel Valley section) The correlation between microfaunal distribution and sequence stratigraphy is discussed. Our study shows that levels containing abundant microfaunas are only located within the transgressive systems tracts (TST) of the sequences, independently of the stratigraphic interval. Thus, the major foraminiferal diversity appears to be related to a sea level rise with results, for the Weser Basin during the Muschelkalk, in the development of a carbonate platform facies.