Objective: This study aimed to investigate the association between overall survival (OS) and activities of daily living (ADL) in patients with skeletal-related events. In this study, 265 patients whose clinical parameters were available before radiotherapy were investigated. Methods: Age, sex, ADL, pain, the primary site, spinal level of bone metastases, spinal instability, treatment strategy, including chemotherapy or palliative treatment, and OS were investigated. ADL patients with a Barthel index of ≥90 were classified as the high ADL group, while those with a score < 90 were classified as the low ADL group. For OS, patients surviving ≥160 days were classified as the non-poor prognosis group, and those who survived <160 days were classified as the poor prognosis group. Results: Age, sex, ADL, pain, the primary site, and treatment strategy for OS were different between the two groups (p < 0.1). Logistic regression analysis revealed that ADL, the primary site, and treatment strategy were significant predictors of OS (p < 0.05). High ADL, breast cancer, and chemotherapy had a positive effect on OS. Conclusions: It is suggested that improvements may be obtained by performing rehabilitation interventions to maintain and improve ADL, by constructing a system for monitoring spinal bone metastases with images before ADL decreases, and by performing interventions such as changes in treatment methods such as RT or surgery at appropriate times.