The thesis focuses on the epistemic (cognitive) character of democratic institutional practices and the protection of basic liberties in Mill's political thought, using it as a basis for the interpretation of institutional political proposals and moral standards within his theory. Mill addresses various issues and offers proposals that often seem to be motivated by different reasons and lead to diverse, sometimes even incompatible, results. I hold that identifying the epistemic criteria within Mill's proposals can serve as a basis for unifying his political thought. Furthermore, it can help us resolve the tension between political and epistemic values present in contemporary discussions. The thesis analyses several underinvestigated ideas in Mill's political thought. It characterizes Mill as an epistemic democrat and sets his theory in the broader explanatory framework related to the justification of collective decision-making procedures. My work follows Mill's sophisticated argumentation from its roots in utilitarian moral theory to its implications in liberal democracy. This thesis has three parts. In the first part (first, second and third chapter), I discuss and elaborate on the two basic criteria Mill uses to evaluate different forms of government (or different decision-authorization procedures). Furthermore, I analyze Mill's argument for the epistemic value of political disagreement, which establishes Mill as an epistemic liberal and represents a foundation for his future characterization as an epistemic democrat. In the second part (fourth, fifth, sixth and seventh chapter), I fully develop the epistemic interpretation of Mill's political thought, arguing that Mill values democracy for its instrumental epistemic qualities. Additionally, I analyze and evaluate epistemic arguments for various mechanisms Mill introduces to filter the public will, thus protecting decision-authorization and decision-making procedures from incompetence, vehemence and negligence. These filtering mechanisms include public balloting, advocacy as a model of political representation, division of epistemic and political labor between the representative body (the parliament) and expert bodies (legislative commissions and executive government), as well as the limited autonomy and authority of the local government. Finally, I emphasize Mill's epistemic justification of plural voting proposal and his views on the epistemic value of partisanship. In the third part of the thesis (eighth chapter), I address the alleged problem of paternalism and indicate how epistemic interpretation can help us preserve consistency in Mill's political thought. The thesis offers a novel interpretation of Mill's political philosophy and discusses its possible application in the contemporary world, particularly concerning the division of epistemic and political labor between the representative and the executive branch of government and the role of experts in democratic decision-making procedures.