Purpose: The purpose of this study was to investigate suicidal ideation and its associated factors according to sex in the elderly, by focusing on socio-demographic and health characteristics. Methods: Data were derived from the fifth Korean National Health and Nutrition Examination Survey (KNHANES V-2, 2011). The subjects were 1,464 elderly aged 65 years or more (620 male and 844 female). The SPSS/WIN 21.0 program was used for data analysis. Results: Suicidal ideation was positively associated with depression and stress in both male and female subjects. For elderly men, those aged 75 years or more, had no spouse, and had activity limitations showed a higher suicidal ideation risk. For elderly women, those who had low a education level and were perceived to be unhealthy showed a higher suicidal ideation risk. Conclusion: Nurses should consider sex differences when designing suicide prevention programs for the elderly.