The present study assessed whether dementia worry is associated with adults’ subjective cognitive difficulties, and whether any associations are moderated by age. Participants were 477 adults aged 18–90 years. They completed standard, subjective measures of dementia worry and everyday cognitive difficulties (i.e. attention, language, verbal and visual-spatial memory, and visual-perceptual ability). Moderated regression analyses included dementia worry as a predictor of specific cognitive difficulties, and age as a moderator. Covariates included gender, trait cognitive and somatic anxiety, general aging-related anxiety, depression, (...) stress, mental health treatment status, and health status. Greater overall dementia worry, and specifically more frequent dementia worry, were both associated with greater attentional difficulty in middle-aged and older adults, but not in young adults. Cognitions about developing dementia in reaction to memory lapses were also associated with greater cognitive difficulties across the adult lifespan for multiple cognitive domains. Results highlight a robust relationship between dementia worry and subjective attentional difficulties, especially in middle-aged and older adults. Worry frequency is also more influential with adult aging. A cognitive or meta-cognitive mechanism may underlie subjective cognitive concerns across the adult lifespan. (shrink)