Abstract. Can Boutet de Monvel's algebra on a compact manifold with boundary be obtained as the algebra ‰ 0 .G/ of pseudodifferential operators on some Lie groupoid G? If it could, the kernel G of the principal symbol homomorphism would be isomorphic to the groupoid C*-algebra C .G/. While the answer to the above question remains open, we exhibit in this paper a groupoid G such that C .G/ possesses an ideal « isomorphic to G . In fact, we prove first that G ' ‰˝K with the C*-algebra ‰ generated by the zero order pseudodifferential operators on the boundary and the algebra K of compact operators. As both ‰˝K and « are extensions of C.S Y /˝K by K (S Y is the co-sphere bundle over the boundary) we infer from a theorem by Voiculescu that both are isomorphic.Mathematics Subject Classification (2010). 58J32, 19K56, 58H05, 58J40.