Purpose: This study is exploratory research to check the survey instrument KDSQ-C used to measure cognition for agreement between the elderly and their caregivers. Methods: Elderly persons from 170 families, who are aged over 65, have never been diagnosed with dementia, and who have caregivers in S City and K City were randomly selected by their nurses. A survey was conducted in the time from September to November, 2009 through personal interviews using a questionnaire. Results: In terms of consistency among items, there was high consistency (0.813) in the responses regarding complex task competence for the statement ``it is hard to reach a destination alone with public transportation``. There was relatively low consistency (0.63) in the responses regard memory for the statement ``they forget an appointment``. When the subject elderly and caregiver live together, as when their children or spouses responded, consistency was greater than when the caregiver lived in a different home. Conclusion: KDSQ-C showed high agreement in measurement between the subject elderly and their caregivers, demonstrating that it can be used as a measurement scale for cognition which can be directly applied to the subject elderly.