Purpose: This study aimed to examine and compare factors in uencing depressive symptoms from those in uencing suicidal ideation in Korean adults aged 20-39 years. Methods: Data were collected from September 15 to 23, 2021 using an online survey company because of the limitations of face-to-face surveys during the coronavirus 2019 pandemic. Participants were also recruited from the Seoul Suicide Prevention Center. Suicidal ideation, depressive symptoms, and general health and demographic characteristics were determined based on existing standardized questionnaires. Multiple logistic regression analysis was used to determine associations with depressive symptoms and suicidal ideation.Results: Based on data from 1014 participants, age, sex, alcohol consumption, sleep duration, and stress were associated with depressive symptoms. In contrast, income, subjective health status, and stress were found to in uence suicidal ideation; the effect of income disappeared when adjusted for depression.Lower income, poor subjective health status, higher stress levels, and depression were associated with a higher risk of suicidal ideation.Conclusions: These ndings suggest that depression and suicidal ideation have distinct in uencing factors and that simply viewing depression as a risk factor for suicidal ideation may lead to other important factors being overlooked. This study emphasizes the need for targeted interventions and prevention strategies to address speci c factors associated with each outcome. Overall, this study provides valuable evidence for developing effective mental-health interventions and policies for young adults. Further research is recommended to delve deeper into the similarities and differences between depression and suicidal behaviors in this population.