Objectives: Persons with progressive cognitive impairment (CI) increasingly rely on surrogate decision-makers for everyday activities. Yet, little is known about changes in everyday preferences over time or about concordance between persons with CI and their care partners regarding longitudinal changes. Methods: The sample included 48 dyads of persons with CI (Clinical Dementia Rating Scale score ≥0.5) and their care partners. The Preferences for Everyday Living Inventory was used to assess importance of preferences among persons with CI at baseline and follow-up (mean 486 days). Care partners separately completed concurrent proxy assessments. Mixed random and fixed effects longitudinal models were used to evaluate changes in ratings and concordance levels between persons with CI and care partners. Results: There were significant gender differences regarding importance ratings of “autonomous choice” and “social engagement” preferences over time: women with CI rated these preferences as more important across time as a whole. Higher levels of neuropsychiatric symptoms were associated with less importance of “social engagement” preferences across time as a whole for persons with CI and a more negative discrepancy between persons with CI and care partner proxy assessments as time went on. Conclusion: This study yields new insights into predictors of longitudinal change in everyday preferences among persons with CI and their care partners. Although preferences were largely stable over time, there is increasing support for the relationship between differences in “social engagement” preferences and neuropsychiatric symptoms, which may have implications for monitoring and/or treatment in the context of cognitive impairment.