The purpose of this paper is to analyze the arguments and strategies developed by regulated professions whose “labor monopolies” are today challenged. Institutional change theory, quality economics, and the sociology of professions provide an analytical framework for understanding why and how professional rules produce and organize labor market “closure” and define unstable professional parameters. The European Commission considers regulated professions unnecessary obstacles which must be lifted in order to stimulate growth. We analyze the origin and consequences of a liberalization of the legal and accounting services market. We study the transformations of these two professional groups whose unity and professional rules are being challenged in a period of deep changes resulting from the construction of Europe and market globalization. Can the market become a place of competition for lawyers and accountants? How does economic and sociological theory view the new increase in professionals and their resistance to this market-opening process?