The paper presents a comprehensive analysis of the interconnected phenomena of the rise of populism and the erosion of factual discourse, known as «truth decay,» in the contemporary socio-political context. The study examines the resurgence of populism in the 21st century, characterized by its deviation from historical populism due to modern economic inequalities and the influence of digital platforms. This contemporary form of populism, driven by cultural anxieties and identity politics, is contrasted with its historical counterpart. The concept of «truth decay» is introduced as a defining feature of this era, marked by a diminishing reliance on facts and rational discourse in public discussions, accelerated by social media and fragmented media environments. The paper highlights how truth decay and populism fuel each other, contributing to a transformation in information consumption, characterized by rapid dissemination and the formation of echo chambers. The research highlights the dynamics of truth decay and its intricate relationship with populism. It delves into how the erosion of factual discourse leads to the spread of disinformation and the manipulation of public opinion, hallmarks of populist strategies. The work discusses the impact of populism in fostering skepticism towards established sources of information and the ensuing reliance on alternative facts. The role of digital platforms in the proliferation of false narratives is analyzed, highlighting their influence on public opinion and the undermining of essential democratic principles such as transparency and accountability. The paper addresses the global implications of truth decay and populism. It emphasizes the phenomenon's role in geopolitical conflicts, elections, and the importance of international cooperation to confront these challenges. The analysis proposes strategies to combat truth decay, including enhancing media literacy, investing in fact-checking, promoting ethical journalism, and encouraging responsible use of technology. The paper underscores the need for embracing diversity and inclusion as countermeasures against populism and the spread of false narratives.