Purpose: This study was done to examine factors that influence quality of sleep and depression in psychiatric patients. Methods: This research study was a descriptive survey and participants were patients hospitalized with psychiatric disorders. Measures were depression and quality of sleep scales. Data were analyzed using t-test, ANOVA and multiple regression. Results: Variables significantly influencing participants’ quality of sleep were depression, level of pain and taking antidepressants. These variables explained 26% of the variance in quality of sleep. Variables significantly influencing participants’ depression were quality of sleep and level of pain. These variables explained 27.0% of the variance in depression. Conclusion: Findings indicate a strong relationship between quality of sleep and depression. More research is needed to better assess quality of sleep and level of depression in these patients. It is important for nurses to recognize the importance of assessing depression and developing and researching nursing intervention programs for inpatients with mental disorders.