Absence of patients without leave is common in psychiatric hospitals, and causes anxiety to staff, relatives, and the lay public. Such incidents are difficult to predict. This study attempted to identify the characteristics of patients absconding from a UK hospital over one year. Numbers were small, as those patients discharged against advice and failing to return from leave were excluded. Absconders were predominantly male, young, compulsorily admitted, and discharged with a diagnosis of schizophrenia. They tended to be single, had many previous admissions, and a longer total length of stay, and the police were more often involved in their admission. Reasons for absconding and the implications for management of newly admitted psychiatric patients are discussed.