With the object of examining the effects of horticultural therapy based on structural recall by developmental stage on cognitive, emotional, and hand functions of institutionalized elderly, this study executed a horticultural therapy program once a week and through a total of 14 sessions during the period from May 2 to December 5, 2013. The subjects of this study were 34 elders admitted to S Geriatric hospital for geriatric diseases, and they were divided into a control group and an experimental group. Because the program was designed for institutionalized elders who were able to do only indoor activities, it provided various seasonal horticultural activities that could be done even in a limited space by giving materials and subjects that could be recalled by developmental stage. The results of this study are as follows. As to changes in cognitive functions (MSQ) after the horticultural therapy program, the control group showed a decrease as having more negative ranks, and the experimental group showed an increase as having more positive ranks, but such changes in the control and experimental groups were not significant. As to changes in emotional functions after the horticultural therapy program, the control group showed a decrease but without significance in ego integrity as having more negative ranks, and the experimental group showed an increase with significance as having more positive ranks (P=0.020). As to the experimental group’s changes in the sub factors of ego integrity, positive ranks increased in all the sub-factors and the increase was particularly significant in satisfaction with present life (P=0.038). As to changes in life satisfaction, the control group showed increased positive ranks but without significance, and the experimental group showed significantly increased positive ranks (P=0.022). As to the experimental group’s changes in the sub-factors of life satisfaction, changes in denial of the past (P=0.029) and denial of the future (P=0.016) were particularly significant. As to changes in hand functions, both the control and experimental groups showed some improvement in pinch after the horticultural therapy program but the changes were not significant. Grip strength did not change in the control group, and in the experimental group right-hand grip strength was improved slightly more than left-hand one, the difference was not significant. The results of this study suggest that horticultural therapy based on structural recall by developmental stage is effective in improving institutionalized elders’ emotional functions and, consequently, can contribute to higher quality of life, which is the ultimate goal of elders.