<b><i>Background/Aims:</i></b> We investigated quantitative/qualitative changes of instrumental activities of daily living (IADL) in people with a Clinical Dementia Rating (CDR) of 0.5. <b><i>Methods:</i></b> IADLs were evaluated in older residents: CDR of 0 (healthy) and CDR 0.5 (questionable/very mild dementia). The subjects with CDR 0.5 were divided into 2 types: the very mild Alzheimer's disease (vmAD) type and the other type including very mild subcortical vascular dementia. IADLs were evaluated quantitatively using the Lawton and the original qualitative IADL scales. <b><i>Results:</i></b> CDR 0.5/vmAD type subjects had impairment of only one Lawton item (Shopping) compared to CDR 0 subjects. However, the CDR 0.5/vmAD type group and the CDR 0.5/other type group showed impairment of 3 items in the qualitative assessment (Shopping, Food preparation, and Mode of transportation). <b><i>Conclusion:</i></b> We suggest using both quantitative/qualitative IADL scales for assessing older adults with very mild dementia.