Background and objective: Music therapy is a non- expensive, non- invasive and applicable nursing intervention that can be applied by nurses and family caregivers in different situations. The purpose of this study was to investigate the effect of selected music on agitation behaviors of elderlies who are suffering from Alzheimer disease and residing at selected nursing homes of Tehran city. Methods: The present study was performed in a Semi-experiential. 34 elderly individuals with Alzheimer who show agitation behaviors were selected and they were randomly divided to two groups: intervention group (n=17) and control group (n=17). The individualized music was collected on CDs based on the elderly peoples’ preferences or if they suffered from severe cognitive impairment, their families were asked to select the music. Subsequently the individualized music was played by headphone in three sessions per week, afternoon and each session lasted for 20-30 minutes during 1.5 month for intervention group. For control group, no intervention was taken and they only received routine daily care measures of nursing homes. Data was gathered in 4 times for groups: Pre Test, Post Test1 (after 9 sessions), Post Test 2(after 18 sessions) and follow up step (a month after intervention). The tools for collecting data include: demographic inventory, Cohen- Mansfield’s Agitation Inventory (1986) and Abbreviated mental test (1972). The data were analyzed by MANOVA/ANOVA test on p 0.05), while after execution of intervention, significant difference was observed in all three measurement stages (p < 0.05). Conclusion: This study supports the effect of individualized music on reduction of agitation behaviors of elderly people who are suffering from Alzheimer’s disease and reside in nursing homes. Paper Type: Research Article