The article examines the impact of collective narcissism, trust and populism on conspiracy mentality among citizens aged 65 and older in Poland. Understanding their behaviours and attitudes is crucial for at least two reasons. First, demographic shifts are leading to a growing proportion of seniors in European societies. Second, as life expectancy increases, older adults remain socially and politically active for longer. This article presents findings from two waves of a longitudinal study (N = 379). Our model confirms that collective narcissism and populism drive generic conspiracist beliefs, while interpersonal and institutional trust have no significant effect.