OBJECTIVE: To assess the independent and combined impact of frailty, multi-morbidity, and activities of daily living (ADL) limitations on self-reported quality of life and healthcare costs in elderly people. DESIGN: Cross-sectional, descriptive study. METHOD: Data came from The Older Persons and Informal Caregivers Minimum DataSet (TOPICS-MDS), a pooled dataset with information from 41 projects across the Netherlands from the Dutch national care for the Elderly programme. Frailty, multi-morbidity and ADL limitations, and the interactions between these domains, were used as predictors in regression analyses with quality of life and healthcare costs as outcome measures. Analyses were stratified by living situation (independent or care home). Directionality and magnitude of associations were assessed using linear mixed models. RESULTS: A total of 11,093 elderly people were interviewed. A substantial proportion of elderly people living independently reported frailty, multi-morbidity, and/or ADL limitations (56.4%, 88.3% and 41.4%, respectively), as did elderly people living in a care home (88.7%, 89.2% and 77,3%, respectively). One-third of elderly people living at home (31.9%) reported all three conditions compared with two-thirds of elderly people living in a care home (68.3%). In the multivariable analysis, frailty had a strong impact on outcomes independently of multi-morbidity and ADL limitations. Elderly people experiencing problems across all three domains reported the poorest quality-of-life scores and the highest healthcare costs, irrespective of their living situation. CONCLUSION: Frailty, multi-morbidity and ADL limitations are complementary measurements, which together provide a more holistic understanding of health status in elderly people. A multi-dimensional approach is important in mapping the complex relationships between these measurements on the one hand and the quality of life and healthcare costs on the other