ON SYMPLECTIC AND CONTACT GROUPOIDS Paulette Libermann Abstract. This paper deals with Lie groupoids, in particular symplectic and contact groupoids. We formulate a definition of contact groupoids; we give examples and a counter-example (groupoid with a contact form which is not a contact groupoid). Keywords. Lie groupoid, symplectic groupoid, contact groupoid, slidings, invertible sections, Lie algebroid.