In long-term care settings, behavioral disturbances are exhibited more often by those residents with some level of cognitive impairment. The extent to which pain influences dysfunctional behaviors, and the extent to which pain manifests itself as dysfunctional behaviors, has not been empirically studied. The purpose of our study was to investigate the relationship between pain and behavioral disturbances among long-term care residents suffering from varying levels of dementia. A cross-sectional study of 277 long-term care residents aged 60 and older was conducted to (1) determine the influence of pain on the number, intensity, frequency, and duration of dysfunctional behaviors; (2) investigate the differences between residents with varying levels of dementia who were suffering from acute pain in the intensity, frequency, and duration of 19 behavioral categories; and (3) investigate the differences between residents with varying levels of dementia who were suffering from chronic pain in the intensity, frequency, and duration of 19 behavioral categories. Results suggest that pain influenced behavioral disturbances among those with severe dementia more often than those with moderate or mild dementia, and residents with chronic pain who have severe dementia exhibit significantly more dysfunctional behaviors than those with earlier-stage dementia. These findings support the utility of comprehensive behavioral analysis involving clinical ratings of intensity, frequency, and duration of dysfunctional behaviors, with the assessment of the resident's level of dementia. Moreover, our results imply that pain and other forms of physical suffering must be adequately treated in order to reduce behavioral disturbances and improve quality of life.