This article is about the way unions are using digital information and communication technologies (DICTs) for experiments in new democratic practices within their organizations. The aim is to understand how such experimenting is shaping the ways of carrying out and imagining representative, participatory and deliberative democracy. Our theoretical approach is inspired by the experimentalist approach and by work on digital democracy. On the empirical level, our article is based on semi-structured interviews with the communications managers of thirteen union organizations in Quebec and on analysis of how these managers use and mobilize DICTs with a view to improving the effectiveness of democratic practices, increasing the extent and intensity of collective participation and mobilization and better aggregating the interests and concerns of different stakeholders. Whereas preceding studies of digital democracy put forward the hypothesis of DICTs causing a horizontalization of democratic practices, our results show that DICTs may be revitalizing representative democracy, notably by improving the flow of internal communication processes. These technologies also seem to be contributing to renewal of participatory and deliberative democratic practices, not only as a lever for mobilization but also as a tool for channelling and disseminating union discourse. On the other hand, our results reveal significant limits to the integrative effects of these DICTs, which for the time being are not radically transforming the democratic functioning of unions. Little has been done to try and provide the voiceless—notably young people, women and visible minorities—with spaces for deliberation. In that sense, DICTs are seldom used to aggregate the interests of marginalized, underrepresented groups. To revitalize union democracy, one should first include such voiceless people in the processes of deliberation and participation. Summary This article is about the way unions are using digital information and communication technologies (DICTs) for experiments in new practices of representative, participatory and deliberative democracy within their organizations. We rely here on the theory of the experimentalist approach and the literature on digital democracy. Semi-structured interviews were carried out with the communications managers of thirteen union organizations in Quebec. Our research findings show that DICTs are not replacing traditional practices but are instead being superimposed on older practices. Our findings also highlight the limits to such experiments, these limits being due not to the intrinsic characteristics of DICTs but to the way these technologies are mobilized and used by actors in the union movement.