OBJECTIVE: Patients with probable Alzheimer's disease often deny or underestimate the severity of their memory impairment. The authors examined the relationships between denial and severity of cognitive impairment and between denial and the presence of depressed mood and sad affect in 128 patients with probable Alzheimer's disease. METHOD: Denial of memory deficit was evaluated by structured interview. Cognition was evaluated with a quantitative examination that assessed performance on 16 subtests. Depression was rated by using a scale that included patients' self-ratings as well as caregivers' and examiners' assessments of the patient's mood and affect. Pearson correlation coefficients were used to quantify the relationship between denial and demographic, cognitive, and depression variables. Stepwise multiple regression analysis was used to further examine the relationship between denial and individual cognitive subset scores. RESULTS: Denial did not correlate with age at onset of Alzheimer's disease, duration of illness, or educational background. It did correlate with gender: women exhibited greater denial than men. A significant correlation was found between denial and overall severity of cognitive deficit and particularly with impairment in object naming. A negative correlation was found between denial and depression. CONCLUSIONS: The association between denial and cognitive impairment may suggest that denial of probable Alzheimer's disease results from disruption of cognitive abilities needed for awareness of illness. The negative association between denial and depression may suggest that depression in Alzheimer's disease is in part reactive in nature.