Purpose: The purpose of this study was to identify the effect of ROK army soldiers’ depression, military life-stress, self-esteem and resilience on suicidal ideation. Methods: Descriptive correlational study design was used. 156 soldiers completed structured questionnaires on depression, military life-stress, self-esteem, resilience and suicidal ideation through self-reporting. The collected data were analyzed using descriptive statistics, one-way ANOVA, Pearson correlation coefficient, and multiple regression. Results: Suicidal ideation had statistically significant correlations with depression (r=.54, p<.001), military life-stress (r=.50, p<.001), self-esteem (r=-.50, p<.001), resilience (r=-.33, p<.001) and perceived physical health related to COVID-19 (r=19, p=.015). Significant factors influencing suicidal ideation were depression (β=.31, p=.027) and self-esteem (β=-.31, p=.003). The total explanatory power of these variables was 36.0%. Conclusion: It is necessary to develop a program to reduce depression and to improve self-esteem in order to prevent suicidal ideation of ROK army soldiers.