The topic of the article is family assistantship -- a new form of family support, implemented in Poland as part of grassroots initiatives of non-governmental organizations and social assistance organizational units, in the period preceding the adoption of the Act on family support and foster care system (act). The appointment of a new professional role, the family assistant, in the social assistance system, or more broadly -- in the context of care and assistance -- was a real challenge to the current practices supporting the family in Poland: tasks, well-established forms of support, as well as the expectations and interests of helpers' professional environments, administration, local authority and other groups. The purpose of the sociological analysis of the processes of conceptualizing and implementing family assistantship in the social assistance system is to justify the thesis that family assistantship in the years 1990-2011 can be seen as a normative innovation (adaptive strategy) in social assistance and social work, which was a consequence of the revolt against the appearance of goals of social assistance and social work, and a response to the expectation of effective action, directed from various sides to social assistance, including from the professional environment of social workers, more and more active in the educational sphere. Also social policy, since the 1990s interested in the issue of the effectiveness of social assistance and social activity, has become an "external" source of inspiration for the institutional change introduced, which was the work of the (social) family assistant and its organizational model. In the presented text I am looking for answers to two questions: 1) what are the characteristic features of family assistantship as normative innovation? 2) what was the social order destabilisation in the years 1990-2011, incurred by including family assistantship in routine practices in social assistance centres? In preparing this study, I used my own research, observation and professional experience, as well as research carried out by other authors. In addition to the main goal, this article also pursues a minor goal. It is an attempt to synthesize dispersed empirical material on the subject of family assistantship, as well as the results of research relating to the processes of implementing institutional change, in an important context of care and assistance that is underrated in sociological reflection. [ABSTRACT FROM AUTHOR]