Focusing on the relatively long standing experience of the neighbourhood councils of Montevideo (1991-current), the paper seeks to analyse how sustainable is democratic innovation? Sustainability is approached through the study of the evolution of citizens participation in elections and running as neighbourhood councillors. We found a decline in levels of participation over time. This is explained as a consequence of an institutional design which seriously limits the performance of neighbourhood councils in terms of its influence on the decision making or the development of civic virtues and political capital.