Abstract: Background: Patient satisfaction is an important goal in the health care system and the length of waiting time is a sensitive matter because it can cause a decrease in the quality of health services in hospitals. The purpose of this study was to determine the effect and causes of length of waiting time of patients in the Emergency Room. Subjects and Methods: This research method is a mixed method with an exploratory sequential approach. The data was collected through interviews and surveys using questionnaires, patient internal transfer sheets, and handover sheets for inpatients. The analysis of the data used content analysis method and SPSS software.