Many patients with severe mental illness are admission in hospital; but little is known about psychiatric re-hospitalization in this population. Our objective was to identify motives of psychiatric re-hospitalization in Dr. Rodriguez Lafora hospital. It is an observational, descriptive and retrospective study. We collected information about patients aged 18 to 64 who were hospitalized during the month of January of 2015 in the acute psychiatric hospitalization by Selene software. We reviewed psychiatric re-hospitalization for 6 months later and the results were analyzed by SPSS software. The percentage of inpatients with a diagnosis of schizophrenia spectrum and other psychotic disorders was 29.4%, 13.7% bipolar disorders, 13.7% personality disorders, 11.8% depressive disorders, 9.8% alcohol use disorders, 3.9% schizoaffective disorders, 3.9% intellectual disabilities, 3.9% adjustment disorders with depressed mood, 3.9% obsessive-compulsive and related disorders, 2% substance-related and addictive disorders, 2% feeding and eating disorders and 2% adjustment disorders with mixed anxiety and depressed mood. The percentage of psychiatric re-hospitalization in patients with alcohol use disorders was 60%, 57.1% personality disorders, 50% obsessive-compulsive and related disorders, 50% schizoaffective disorders, 28.6% bipolar disorders, 26.7% schizophrenia spectrum and other psychotic disorders and 0% in the other inpatients. Why the percentage of psychiatric re-hospitalization is higher in patients diagnosed with personality disorder and alcohol use disorders? It would be important to establish an approach through more appropriate units as alcoholic detoxification unit and personality disorders unit.