Ideological indoctrination is a powerful tool for parties in armed conflicts, as they provide a source of motivation for combatants to stay in-group under difficult circumstances, and to perform actions that either put them in the line of risk or defy their personal ethical codes. But once in peacetime, besides the effects of past negative inter-group experiences, radical beliefs may become an obstacle to reconciliation, and help to prolong the confrontation in the minds of ex-combatants. An examination of 484 recently decommissioned soldiers and insurgents in Colombia show how the persistent ideological differences among former enemies help us explain post-conflict intergroup bias, beyond the effects of wartime victimization. We conclude that addressing the ideological radicalization that prolong confrontation after armed conflict ceases is fundamental to create proper conditions for reconciliation, and it offers a viable policy alternative to the much-needed healing from wartime-related trauma.