Purpose. The purpose of this study was to identify the factors affecting quality of sleep and sleep disturbance among inpatient. Methods. A descriptive correlational study was conducted Participants were 200 inpatient in a hospital located in B city. A structured questionnaire was used for data collection. Collected data were analyzed using descriptive statistics, t-test, one-way ANOVA, Pearson's correlation, and stepwise multiple regression. Result. Hospitalized patient's score of sleeping quality was 38.26 on an overall scale of 60, indicating it to be higher than 'Medium (30 points). Almost hospitalized patient in this study suffer from sleep disturbances. As results of univariate analyses, Educational level, Departments, Why hospitalized, Insomnia / depression, Chronic Disease, Scale of pain, physical symptoms, environmental factors, emotional factors, and sleep promoting behavior, disturbed sleep among hospitalized. However, the result of stepwise multiple regression analysis identified that physical symptoms, environmental factors, emotional factors, sleep promoting behavior, and Why hospitalized disturbed sleep and were significant score of sleeping quality for hospitalized and these sleep disturbance factors accounted 46.8% of variance of sleeping quality among hospitalized. Conclusion. These findings suggest that hospitalized patients with poor sleep quality should have their health carefully screened for physical symptoms, environmental factors, emotional factors, sleep promoting behavior, and why hospitalized. In addition, we recommend the development of a nursing program for improving sleep quality.