The need for accurate local information on the scale, nature and outcome of absconding or Absence Without Leave (AWOL) from an independent UK psychiatric hospital led to this 3-year (1997-1999) retrospective analysis of of AWOL data. One hundred and forty-eight AWOL incidents involving 88 patients were identified. Absconders were found to be significantly younger, more likely to be detained upon admission and more likely to be unmarried than a control group (n = 1378) of non-absconders. There were no significant differences for sex, length of admission or ethnicity. Descriptive data on the circumstances surrounding AWOL events are given, with at least 24 (16.2%) incidents having serious adverse outcomes. Baseline absconding rates are presented for the specialist clinical divisions within the hospital. There is a need for more detailed studies of absconding by patients within the Adolescent Mental Health Service subgroup where the absconding rate was relatively high and engagement in risk activity whilst AWOL relatively frequent.