Despite several studies of absconding from mental hospitals, what the hospitals and the police do following a patient absconding from a mental hospital has been largely ignored. This article fills that gap. It looks at the procedure followed by three conventional mental hospitals in south-east England and the procedure followed by the three Police Forces in those hospitals' catchment areas. It is based on twelve months of fieldwork, during which period the policy files of all the hospitals were studied and, among other things, interviews were carried out with a cross-section of both the hospitals' staff and police officers. The crucial factors determining the type of action taken by the hospitals or the police were found to be whether the matter was one of grave concern and whether the absconder was a compulsory patient. Certain aspects of the procedure were found to be unsatisfactory and suggestions for improving them are made.