This study aimed to investigate the long-term effects of group music therapy on agitation manifested by nursing home residents with Alzheimer's disease. A non-randomised experimental design was employed with one group receiving weekly music therapy (n = 26) and another group receiving standard nursing home care (n = 19). Agitation levels were measured five times over one year using the Cohen-Mansfield Agitation Inventory (Cohen-Mansfield, J. (1989). Agitation in the elderly. In N. Billig & P. V. Rabins (Eds.), Issues in geriatric psychiatry (pp. 101-113). Basel, Switzerland: Karger). Although music therapy participants showed short-term reductions in agitation, there were no significant differences between the groups in the range, frequency, and severity of agitated behaviours manifested over time. Multiple measures of treatment efficacy are necessary to better understand the long-term effects music therapy programs have on this population.