Objective: To assess the prevalence, antecedents, and consequences of unawareness of memory impairment in dementia. Method: Persons (n = 1,862) from a geographically defined community without dementia at enrollment subsequently underwent clinical classification (248 with dementia, 611 with mild cognitive impairment, 1,003 with no cognitive impairment), memory testing, and self-appraisal of memory. Memory performance was regressed on self-appraised memory, and the residuals served as an index of memory awareness. After clinical classification, participants completed brief cognitive testing at 3-year intervals for up to 15 years. Results: When unawareness was defined as a score at or below thresholds ranging from the 15th to 25th percentiles, it was more common in dementia (67%–83%) and mild cognitive impairment (15%–33%) than in no cognitive impairment (2%–6%; all p < .001). A continuous measure of awareness (M = 0.00, SD = 0.61) was reduced by 0.37-unit in mild cognitive impairment (SE = 0.04, p < .001) and 1.04-unit in dementia (SE = 0.06), p < .001) compared with those without cognitive impairment, and these associations were weaker in Black persons than White persons (estimate for dementia by race = 0.37, SE = 0.12, p = .003; estimate for mild cognitive impairment by race = 0.30, SE = 0.08, p < .001). Higher premorbid neuroticism was associated with better memory awareness in dementia. Higher memory awareness was not related to mortality in mild cognitive impairment or dementia but had a marginal association with slower cognitive decline in mild cognitive impairment. Conclusions: Unawareness of memory impairment is a common manifestation of dementia, particularly in White persons, but is not strongly related to adverse disease outcomes. (PsycINFO Database Record (c) 2018 APA, all rights reserved)