OBJECTIVES:Delirium is a condition which often are seen in elderly inpatients. It causes complicated symptoms such as confusion and agitation that provide a lot of burden to patients, health providers and patients’ family. There are several randomized controlled studies of multifactorial intervention which enable early recover from delirium but its cost-effectiveness is still uncertain. Objective of this study is to assess cost-effectiveness for our multifactorial intervention towards delirium remission, using real-world data. METHODS:We have implemented three multifactorial intervention at St. Luke’s International Hospital form 2017-2018, which includes 1）team round by specialists of psychosomatic internists and nurse practitioners, 2）establishment of prescription monitoring and 3）Providing rehabilitation program by occupational therapists. We used a real world data to investigate its cost-effectiveness, utilizing Markov model. RESULTS:the multi-factorial intervention was cost-effective when compared to historical data without implementation of interventions. It was associated with ICER of £30,546 using a cost-effectiveness threshold of £50,000 per quality-adjusted life year (QALY). CONCLUSIONS: Our real-world data analysis has shown that multi-factorial intervention for delirium was cost-effective among elderly inpatients. Medical health care providers should consider to apply this strategy as a standard care when elderly inpatients caused a delirium complication.