Appears in collection : Reductive groups and automorphic forms. Dedicated to the French school of automorphic forms and in memory of Roger Godement.

J. Arthur has classified irreducible tempered representations of classical p-adic groups. C. Moeglin has singled out parameters of cuspidal representations among them. Further, she gave a simple formula forcuspidal reducibilities (in the generalised rank one). In our talk, we shall discuss possibility of describing unitarizability of classical p-adic groups (in the case of any generalised rank) based only on the cuspidal reducibilities, and explain how one can get this in the case of generalised rank three.