Background: Sleepqualityis an important factor for health.Sleep quality is directly related to and affecting the overall health state and increased risk of psychological disorders. Aim: the objective of this study was to assess relationship between sleep quality and depression, anxiety and stress in hospitalized psychiatric patients. Subjects and method: a descriptive correlational research design was used to conduct this study; a total sample of 100 psychiatric patients was recruited from inpatient units of Mental Health and Addiction Treatment Hospital at Minia Governorate. Demographic and clinical data were driven from all patients then Pittsburg sleep quality index was utilized to estimate sleep quality and DASS (Depression, anxiety and stress scale) was filled out for depression, anxiety and stress. Results: From all psychiatric patients (47%) of them had extreme level of depression, (68%) of patients had extreme level of anxiety and (42%) of them had stress. Most of patients (94%) had poor sleep quality. A strong significant correlation was found between depression, anxiety, and sleep quality while no statistically significant correlation between sleep quality and stress. Conclusion: thecurrent study findings reflect that many of hospitalized psychiatric patients were suffering from poor sleep quality. It seems that sleep quality was related to depression and anxiety but there was no significant association between sleep quality and stress. Recommendations: More efforts should be undertaken to identify possible different factors that can be related to poor sleep quality during hospitalization. A compelling need for further researches regarding nursing interventions aimed at improving sleep quality of hospitalized patients.