The analysis of this essay is based on the fragmentary legislation on co-operative societies. In details, a possible combination between co-operative societies and forms of organised voluntary service is taken into account, under the view of non-profit organisation and labour in non-profit organisation. Moreover, the essay examines the State intervention in the social co-operation in order to deal with psychological-physical or social-economic disadvantages which affect some categories of citizens in a liberalised and competitive market. At last, it is analysed a prospect of partnership between public and private in the welfare reform, the so-called welfare mix, which involves the co-operative societies in their privilegiate relationship with public administration. In the last part of the essay, the author highlights how the discussed problems lead to the importance of social co-operation in the labour law field.