Post-civil war democratization is a critical element of building sustainable peace in the post-civil war states. At the same time, studies of democratic transition and survival suggest that the post-civil war environment is not hospitable to either the transition to or survival of democracy. The post-civil war environment is contentious. Former protagonists are fearful about their security and at the same time they want to protect their political and economic interests. The central argument of this study is that former rivals can agree to a transition toward democracy to the extent that a stable balance of power exists between the government and rebel groups, a balance that eliminates the sort of security dilemma that would encourage one or both to resume armed conflict. And the balance should ensure access to political power and economic resources. This study identifies factors that contribute to the establishment of such a balance of power between former protagonists and factors that affects its stability. These factors should affect the decision of former protagonists on whether or not they can achieve their political and economic interests if they agree to a transition toward democracy once civil war ends. Factors that are conducive to a transition toward democracy are different from factors that sustain that transition in post-civil war states. Post-civil war democracies are fragile. The side that won the democratic election can dismantle institutions of democracy and repress oppositions. The fear of being repressed could create stronger incentives for the opposition groups to return to conflict. To address this puzzle, I develop a conceptual framework that explains how costs of the previous civil war, the establishment of inclusive institutions and the higher level of economic development create incentives for the former rivals to sustain democracy. Hypotheses derived from the theoretical implications are tested by using survival analysis.