Abstract: Aggression and violent behavior are the chief concerns among staff, families and clients at inpatient psychiatric units. The aim of this study was to assess psychological loneliness, and aggression among psychiatric patients. Descriptive correlational research design was used in this study. The sample consisted of 100 psychiatric inpatients at Beni-Ahmad psychiatric hospital in El-Minia governorate. Three tools were utilized to measure the concepts of the study variables: Personal and clinical data Questionnaire, Psychological loneliness scale, and Aggression questionnaire. Results of the study revealed that 42%, 35% and 14% of patients were diagnosed schizophrenic, depression and manic disorders. Most of them (73%) had severe psychological loneliness and 51% had severe level of aggression. In conclusion, more than half of psychiatric patients had severe psychological loneliness and severe level of aggression. Psychological loneliness was negatively correlated with aggression, Recommendations: This study recommended to design and implement a psycho-educational program to decrease psychological loneliness and aggression among the psychiatric patients.