Purpose: The purpose of this research was to evaluate the effect of horticultural therapy on cognitive function, self-esteem, depression and activities of daily living of elderly with dementia. Method: The research design was an one group pre and post-test study design. The subjects of this study were 7 elderly with dementia in K elderly institution in Daegu. Instruments used in this research were MMSE-K(Mini-mental state Examination Korean Version) developed by Kwon & Park, SES(Self-Esteem Scale) developed by Rosenberg. SDS(Self-Rating Depression Scale) developed by Zung and BADL(Bathel Activity Daily Living) developed by Bethel. One-hour horticultural therapy was offered to the study participants weekly for 12 weeks. Results: The results showed that self-esteem was significantly increased after the horticultural therapy. However, in terms of cognitive function. depression and ADL, there was no significant change after the horticultural therapy among these elderly. Conclusion: In this research. there were no obvious change in cognitive function. depression, and ADL after the horticultural therapy among participants. Although the difference was not statistically significant. descriptive statistics showed some difference in scores on these variables after the intervention. So, it is suggested to conduct a further research with larger samples and pre and post-test design with control group.