Delirium is a common complication among patients in ICU settings. Although it has been repeatedly confirmed that Confusion Assessment Model for Intensive Care Unit (CAM-ICU), one of the most commonly used ICU delirium assessment tool, is highly accurate in validation studies, it's sensitivity and specificity is relatively low during routine practice among bedside nurses. The aim of this study is to develop a mobile application (app) to detect delirium and to test its reliability and validity both by research nurses and among ICU bedside nurses. The app was programmed with Java and installed on a mobile device with Android system. After completion of reliability and validity testing, the app will be integrated into the existing Hospital Information System in order to automatically retrieve essential information for risk factor identification and formulation of care plan accordingly to prevent or manage ICU delirium.