This study aimed to develop a prediction model for post-operative delirium among older patients receiving elective orthopedic surgery and to evaluate its effectiveness in predicting long-term health outcomes. This prospective cohort study screened all subjects aged over 60 years who were admitted for elective orthopedic surgery in a tertiary medical center in Taiwan from April, 2011, to December, 2013. Demographic characteristics, surgery-related factors, and results of comprehensive geriatric assessment (CGA) were all used to develop the prediction model. Long-term health outcomes, including mortality, nursing home admission, and functional status in the first year after surgery, were used to further evaluate the effectiveness of the prediction model. Overall, 461 patients (median age, 73 years; interquartile range [IQR], 67-80 years; 42.3% males) were enrolled, and 37 patients (8.0%) developed post-operative delirium. Prediction models were developed on the basis of demographic characteristics and surgery-related factors (model 1) and of demographic characteristics, surgery-related factors, and geriatric assessment variables (model 2). Although both models effectively predicted the occurrence of post-operative delirium, duration of post-operative delirium, total hospital days, nursing home admission, and mortality, model 2 was more likely to differentiate cases with functional decline during the first year after surgery. In conclusion, a prediction model developed by using demographic characteristics, surgery-related factors, and results of CGA was highly predictive for post-operative delirium, as well as long-term health and functional outcomes.