BACKGROUND: Modern societies are seeing a steady rise in individuals living alone. This study examines the impact of dietary habits, physical activity, and perceived health status on the health-related quality of life (QoL) of adults aged 40 and older with chronic diseases, comparing living-alone households to multi-person households. METHODS: Data from the 2022 Korean Community Health Survey, including 65,861 respondents, were analyzed. The analysis utilized the Rao-Scott χ RESULTS: Individuals living alone were more likely to be female, older, less educated, economically inactive, divorced or separated, and have lower household incomes compared to those in multi-person households. Physical activity, perceived health status, and QoL were higher in multi-person households. Although all variables influenced QoL in multi-person households, nutritional labeling awareness and frequency of physical activity showed no significant association with QoL in living-alone households. CONCLUSION: Living-alone households with chronic diseases face notable demographic disparities. Additional research is needed to understand why nutritional labeling awareness and physical activity frequency do not significantly affect QoL in this group. The influence of mental health warrants further investigation to guide targeted interventions.