This study explored retirement preparation among the “sandwich generation,” extending beyond financial preparation to a comprehensive life-planning approach. The responses from 3,217 aged 50-64 with surviving elderly parents and adult children aged 25 or older were analyzed using the data from the ‘2020 Korean Family Survey.’ The retirement preparation among the sandwich generation varied according to financial security and life planning. Although many respondents had financial resources, 60.9% exhibited low levels of life planning, highlighting the need for policies promoting both aspects. Contrary to expectations, non-caregivers were more vulnerable in retirement preparation, suggesting financial support to family members might belong to socioeconomically advantaged groups, enabling them to prepare for retirement more effectively. Socioeconomic status plays a crucial role in determining retirement preparation. Those with a lower subjective economic status were more likely to be unprepared. The “insufficient life planning” and “completely unprepared” groups faced greater socioeconomic disadvantages. Household composition and family health also significantly influenced retirement preparation. Households with cohabiting parents and children were more vulnerable in retirement preparation. In addition, poorer family health was associated with weaker retirement preparation. In conclusion, the retirement policies for the sandwich generation should integrate structured life planning alongside financial preparation. Special attention must be given to socially and financially vulnerable groups to prevent old-age poverty through targeted financial support and enhanced social safety systems. Strengthening pension systems and providing financial assistance are essential to reduce economic insecurity in old age.