Previous studies have focused on the relationship between multi-morbidity, frailty, and anemia or functional disability alone rather than in combination. This study aimed to explore the impacts of multi-morbidity, hemoglobin levels, and frailty on functional disability simultaneously in older adult residents of long-term care facilities. This was a cross-sectional study. Data were retrieved from the electronic health records of eight long-term care facilities. Data from a total of 352 subjects aged at least 60 years and residing in these facilities for at least 6 months were analysed. Analytic datasets included the Barthel Index of Activities of Daily Living, the Frailty Phenotype Criteria, the number of chronic diseases, hemoglobin levels, age, and gender. The final model demonstrated acceptable goodness-of-fit indices, namely goodness-of-fit index, comparative fit index, and incremental fit index ≧0.90, root mean square error of approximation <0.08, and insignificance of χ2 (P > 0.05). Frailty, multi-morbidity, and hemoglobin levels all had direct associations with functional disability (all P < 0.001). Hemoglobin levels had a direct association with frailty (ß=-0.11). Multi-morbidity had an indirect association (ß=0.04) with functional disability through hemoglobin levels. Hemoglobin levels had an indirect association (ß=0.05) with functional disability through frailty. The impacts of multi-morbidity, hemoglobin levels, and frailty on functional disability were explored. A high-quality disease management program, interventions for the prevention of frailty, and the provision of continued education for staff about reducing progressive frailty and functional disability for older adult residents are recommended. Geriatr Gerontol Int 2021; 21: 532-537.