Research has shown that repeated statements are rated as more credible than new statements. However, little research has examined whether such "illusions of truth" can be produced by contextual (nonmnemonic) influences, or compared to the magnitude of these illusions in younger and older adults. In two experiments, we examined how manipulations of perceptual and conceptual fluency influenced truth and familiarity ratings made by young and older adults. Stimuli were claims about companies or products varying in normative familiarity. Results showed only small effects of perceptual fluency on rated truth or familiarity. In contrast, manipulating conceptual fluency via semantic/textual context had much larger effects on rated truth and familiarity, with the effects modulated by normative company familiarity such that fluency biases were larger for lesser-known companies. In both experiments, young and older adults were equally susceptible to fluency-based biases.