BACKGROUND In response to the hurricane-related deaths of nursing home residents, there has been a steady increase in the number of facilities that evacuate under storm threat. This study examined the effects of evacuation during Hurricane Gustav on residents who were cognitively impaired. METHODS Nursing homes in counties located in the path of Hurricane Gustav were identified. The Minimum Data Set resident assessment files were merged with the Centers for Medicare enrollment file to determine date of death for residents in identified facilities. Difference-in-differences analyses were conducted adjusting for residents' demographic characteristics and acuity. RESULTS The dataset included 21,255 residents living in 119 at risk nursing homes over three years of observation. Relative to the two years before the storm, there was a 2.8 percent increase in death at 30 days and a 3.9 percent increase in death at 90 days for residents with severe dementia who evacuated for Hurricane Gustav, controlling for resident demographics and acuity. CONCLUSIONS The findings of this research reveal the deleterious effects of evacuation on residents with severe dementia. Interventions need to be developed and tested to determine the best methods for protecting this at risk population when there are no other options than to evacuate the facility.