We introduce, for a reductive p-adic group, a notion of split fundamen
tal stratum of positive level playing the expected parr in the type th
eory of Bushnell and Kutzko. in particular we prove that a smooth repr
esentation containing such a stratum cannot be supercuspidal. The idea
consists in deforming the stratum so that the Abelian character assoc
iated with the deformed stratum will be contained in the representatio
n and will verify a ''good'' intertwining formula. (C) Academie des Sc
iences/Elsevier, Paris.