Purpose As the baby boomer generation moves into old age, the characteristics of the older population are changing. This study aimed to compare the prevalence of depression and suicidal behavior and examine the different impacts of sociodemographic risk factors based on two nationwide cross-sectional studies conducted a decade apart.Methods We compared representative samples of participants aged 60–74 years from two nationwide surveys in 2011 and 2021. Depression and suicidal behavior were assessed using the Korean version of the Composite International Diagnostic Interview, and the prevalence rates were compared according to study year and gender. We used multivariate logistic regression to determine how sociodemographic risk factors affected depression and suicidal behavior in each study period.Results The prevalence of depression in older adults was higher in 2021 than in 2011, with a notable increase among older men. The prevalence of suicidal behavior was slightly decreased but not statistically confirmed. In 2011, being female was the only risk factor for depression; however, several sociodemographic factors, including non-married, low income, and high education level, were identified as risk factors for depression in 2021. The impact of low-income status on both depression and suicidal behavior was twice as much in 2021 as it was in 2011.Conclusion The prevalence of depression has increased compared to a decade ago, especially among older men. Recently, sociodemographic risks have become more important in late-life depression and suicidal behavior. Mental health promotion for older adults needs to consider sociocultural characteristics and environmental changes.