Luigi Gui, social worker, Researcher in General Sociology at the University of Trieste, outlines the professional profile of the social worker based on an historical retrospective and then addressing the still lively debate on the evolution of the social work profession from a scientific perspective. He analyses old and new competences and advocates the adoption of an ecological perspective in social work, open to the integration and contamination of knowledge, which offers social workers a new opportunity to escape from the narrowness of defensive identity boundaries, as long as they can clearly recognise their own professional centre of gravity and conceptual heritage.