Background: Patient`s self-discharge from the hospital is a process in which a patient leaves the hospital before completing his or her determined treatment period by his own will. This study is aimed to survey the factors affecting patient`s self-discharge from the hospital in emergency ward of a referred hospital. Materials and Methods: This is a case-control study. The 280 selected samples were divided to two groups, each with 140 members. The data were gathered using a questionnaire evaluating the scale of patients and their companions` satisfaction of the hospital services. Chi-square test was used for analyzing the relationship between independent variables and the patient discharge type. Moreover logistic regression was used in order to identify the effect of significant independent variables on own will-discharge possibility. Results: Results indicate that there is a meaningful relationship between variables such as age, having supplementary insurance, residency, income rate, reference shift, reference day, satisfaction of the physicians, satisfaction of the physical environment and welfare facilities, the patient`s satisfaction, the waiting time, satisfaction of the instructions given by nurses and physicians and total satisfaction with discharge type(p<0.05). Conclusion: The matter of patient`s self-discharge is a multi-dimensional phenomenon and depends on patient’s characteristics and structural and medical factors. Therefore predicting its scale and determining factors might play an effective role in controlling this phenomenon.