The literature on deliberative mini-publics (DMPs) establishes a link between political dissatisfaction and support for DMPs. However, little is known about the sources of political dissatisfaction that trigger this support. Our research tackles this specific question and claims that citizen dissatisfaction is rooted in a position of ‘losers of representative democracy’, which leads citizens to be more open to reforms that move away from the representative model. Building on the literature on loser's consent, we focus on the effect of voting for a party not associated with the government and of descriptive and substantive (under)-representation in support of DMPs. We rely on a comparative survey conducted across fifteen Western European countries. Supporters of opposition parties and those who are badly represented, both descriptively and substantively, are more supportive of DMPs. These findings have important implications for understanding the public appeal for deliberative democracy instruments.