Sociologists interested in professional work and occupations have differentiated professionalism as a distinctive and special way of controlling and organizing work and workers, with real advantages for both practitioners and clients. In this interpretation the analysis of professionalism is as an ‘occupational value’. But professionalism is changing and being changed as professionals now increasingly work in large-scale organizational workplaces and sometimes in international firms. This article explains professionalism as an occupational value and indicates both the changes to and continuities in professionalism in these organizational contexts. Then some of the possible consequences of the redefinition of professionalism are examined for practitioner-workers and their clients in public sector service work such as health, welfare and education. These consequences include changes in the work itself, in practitioner—employer and practitioner—client relations, and in the control of work priorities and processes. The final section considers if there might also be some advantages in the combination of professional and organizational logics for controlling work and workers and whether there are opportunities associated with these changes which might improve both the conduct and practice of professional service work, while being of benefit to practitioners and clients.