Pathways and processes of professional formation are influenced by relations between professional associations, educational institutions and employing organisations, notions of professional knowledge, and the organisation of professional work. This article advances the use of a productive systems approach to the analysis of professional formation, articulating this with concepts developed in the sociology of educational knowledge and workplace learning that identify how knowledge is appropriated and transformed for professional practice. It is suggested that at different stages of the "production' of professionals the dynamics of formation alter as certain organisations or actors exercise particular influence over a given process or activity. The maintenance of certain forms of social and technical infrastructure, interwoven throughout the stages of production, may facilitate co-operation, aligning goals and reducing tensions in the process of formation. The role of the professional association as a vehicle for formulating the specific logic of the profession, and for brokering relations between key organisations, is examined. Examples from two professions based in the United Kingdom illustrate how the character of professional formation is shaped by how knowledge is valued, the capacity to involve employers in formation processes, the level of engagement that professionals enjoy with other professionals as part of formation, and by the degree of specificity or flexibility legitimated in the pathways constructed.