Purpose: The purpose of this study was to investigate the prevalence of depression and suicidal ideation in elders with dementia and to identify factors influencing their suicidal ideation. Methods: A descriptive and cross-sectional study was conducted from February to March, 2011. The participants were 298 older adults whose MMSE-KC score was 15 to 23. Collected Data were analyzed using t-test, ANOVA, Pearson correlation coefficients, and stepwise multiple regression. Results: According to the Geriatric Depression Scale (GDS) classification criteria, 86.2% of the elders in this study exhibited depression (GDS=5), and 31.5% manifested severe depression. The mean score of suicidal ideation was 5.70 (range 0-20). The risk factors for suicidal ideation were depression, suicidal attempt experience, present location for care, and activities of daily living. Conclusion: The results of this study can be utilized in the development of suicide prevention programs for older adults with dementia. In particular, depression should be screened and managed to reduce suicidal ideation of older adults with dementia.