Vocabulary control is a commonly accepted practice in the library world and is slowly but surely infiltrating museum documentation practices. The need for precise and standardized terminology extends, however, beyond registration and curatorial functions into the sphere of conservation activities and wherever else conservation-related information is recorded and communicated. While vocabulary lists and thesauri for generally describing and classifying museum objects are moving towards maturity, a project to develop a multilingual and broad-based conservation thesaurus has not yet been undertaken. The Getty Conservation Institute (GCI) has long recognized the need for a conservation thesaurus. Over the past five years, the necessary groundwork has been laid to undertake such a project by identifying vocabulary sources and potential applications and assimilating the experience of contemporary thesaurus projects. This summarizes Getty efforts to develop a conservation thesaurus, to outline a recently proposed thesaurus conceptual framework, and to suggest areas in conservation documentation where a conservation thesaurus can be applied.