The purpose of this study was to identify the psychiatric and social factors associated with multiple admissions, especially for psychotic patients. Demographic and diagnostic information (based on the DSM-III-R) was collected on a computerized database for all patients admitted to the only psychiatric hospital in Geneva, Switzerland. Patients who had had at least three admissions over a period of 1 year were compared with a control group drawn from the total clinic population. In 1994, a total of 1575 patients were hospitalized, and 18% of these patients were readmitted for the third or more time. The principal diagnoses were psychotic disorders (25%), affective disorders (35%) and substance-related disorders (24%). The predictors of multiple admissions for psychotic patients were a comorbidity of substance-related disorder, longer duration of illness, female sex, younger age and poorer psychosocial adjustment during the past year. These results highlight the usefulness of a computerized psychiatric database. Indeed, early identification of the types of psychiatric patient who are likely to be readmitted is necessary to enable the planning and implementation of specific programmes of ambulatory care to prevent rehospitalization.