This lecture given at the Journées d'études of the French Association des Conservateurs in May 1962 gives a general view of the main types of synthetic resins, their properties and use, a description of the various products in accordance with methods of transformation (thermoplastic and heat hardening resins) and methods of transformation for museums. The last part of this article deals with the use of plastics for such things as museum equipment, casts and supports, protective coatings, restoration of paintings. -- AATA