OBJECTIVES: To compare measurement properties of caregiver-rated EQ-5D-3L and HUI3 in assessing patients with dementia in Singapore METHODS: In this mainly cross-sectional study, family caregivers of patients with dementia attending a tertiary hospital were interviewed using EQ-5D-3L and HUI3 for proxy ratings of the patients. We evaluated construct validity by examining associations of EQ-5D-3L and HUI3 scores with clinical variables that categorized patients into different groups of contrasting health status. The ability to detect differences in the known groups was assessed using relative efficiency statistic and effect size. The degree of agreement between the two instruments was assessed using the interclass correlation coefficient (ICC) and a Bland-Altman plot. ICC was also computed to estimate the test-retest reliability of each instrument in a subset of the caregivers who did multiple asessments. Acceptability in terms of completion rates, floor and ceiling effects were evaluated.  RESULTS: