Objective: To investigate the factors associated with discrepancies between patient and caregiver reports of the quality of life of patients (QoLp) with Alzheimer"s disease (AD). Methods: Cross-sectional analytic study of 141 patients and their caregivers. The instruments used were the Quality of Life in AD (QoL-AD), the Global Deterioration Scale (GDS), the Geriatric Depression Scale (GDS-d) and the Anosognosia Questionnaire Dementia (AQ-D). Differences were analyzed according to GDS stage. A linear regression analysis was conducted using the difference between the absolute QoLp scores of patients and caregivers. A cluster analysis involving the patient variables was then performed. Results: The discrepancy between patient and caregiver QoLp ratings increased in line with GDS stages (χ2 (2) = 8.7, p = 0.013). In the regression model (F [7,133] = 16.6, p <0.001; R2 = 0.477), discrepancies in QoLp reports were associated with greater anosognosia, less depression and a better cognitive status in patients, as well as with female gender among caregivers. The cluster analysis showed that patients with the lowest ratings of QoLp had a better cognitive status, more depression and less anosognosia. Conversely, the highest ratings were given by patients with a poorer cognitive status, less depression and greater anosognosia. Conclusions: The factors associated with greater discrepancies between patient and caregiver ratings of QoLp were severity of dementia, anosognosia, depression and cognitive status in patients, and female gender in caregivers. In patients with advanced dementia, greater anosognosia leads to more positive ratings in QoLp and complementary observations are required.