The rise of post-truth politics marks the most serious crisis of Western liberal democracy since the end of the Cold War. The decline of trust in expert knowledge and mainstream media, the rise of social media devoid of a gatekeeping function and the growth of covert external interference in electoral processes have led to fragmentation, polarization and destabilization of Western democratic systems. What makes post-truth politics so difficult to resist is its apparently democratic character that claims to challenge bureaucratic depoliticisation, the rule of experts and the disappearance of alternatives to the hegemonic policy. Biopolitics after Truth refutes this interpretation, arguing that the post-truth ideology leads to the degradation of the public sphere that is essential to democratic governance. Rather than enable resistance to expertise-based biopolitical governmentalities, truth denialism dissolves the only framework where their contestation and transformation could take place. In contrast, Biopolitics after Truth argues for a positive role of truth-telling in the democratization of biopolitical governance.