The article discusses the principles and methods of terminology and terminological research. With respect to the needs of translators, terminological research is carried out in order to provide not only the terms used in a given subject field, but their equivalents in one or several other languages as well. This type of research, commonly referred to as comparative terminology, encompasses the principles and techniques applied in a unilingual context, as well as those aspects pertinent to the field of translation. As research carried out by the Terminology Directorate of the Department of the Secretary of State of Canada is primarily bilingual in scope (English and French), this article deals with the practice of comparative terminological research within the Directorate.