Comparing sociological and economic approaches to professionalism yields some insights into a more general theory of the origins and consequences of professionalism. In both sociology and economics, a similar debate distinguishes two competing theoretical approaches. The free market approach in economics is analogous to the power theory in sociology, and the free market approach contributes to explaining which occupations are successful in the political movement accompanying professionalization and to specifying the economic costs of professionalism. Analogous to the structural-functional approach in sociology is the “market failure” perspective in economics, which is rooted in the recognition that some services are delivered under conditions of informational asymmetry between producer and consumer. A general theory of professionalism in sociology should incorporate both the structural-functional and power approaches and should be informed by findings from economics. © 1986, SAGE PUBLICATIONS. All rights reserved.