The purpose of this study was to investigate the balance reaction characteristics of dementia patients according to sensory conditions and to find out what kind of relationship there was between balance performing ability and activity daily living (ADL) of dementia patients. The subjects were 28 dementia patients. Mini-mental status examination-Korea (MMSE-K), clinical test of sensory interaction and balance(CTSIB), Berg balance scale(BBS),and Bathel index(BI) were used to evaluate the balance reaction and ADL from August 15 to September 31, 2001. The date were analyzed with one-way ANOVA, correlation test, using SPSS Windows(version 10.0). The results were as follows: 1. In terms of balance reaction of the dementia patients according to visual conditions, there was found a statistical significance in case of normal floor condition(p<0.05). After the post verification, the balance reaction was significantly when the subject had their eyes closed on the normal floor condition. 2. In terms of balance reaction of the dementia patients according to floor conditions, there was found a statistically significant difference between on the normal and soft floor with the subject's eyes open(p<0.01), between on the normal and soft floor with their eyes closed(p<0.001), and between on the normal and soft floor with visual hemisphere worn(p<0.001). 3. In terms of balance performing ability according to sex, age, and period of onset, there was found no statistically significant difference(p>0.05). 4. In terms of activity daily living according to sex, age, and duration of onset, there was found no statistically significant difference(p>0.05). 5. In terms of the correlations among balance performing ability, activity daily living and the cognitive function of the dementia patients, there were found significant correlations between balance performing ability and activity daily living(p<0.001).