The development and content of a scale to measure indirect self-destructive behaviour (ISDB) among chronically ill medical patients is described. Findings for a sample of predominantly elderly, male, chronically ill patients indicate a generally high incidence of ISDB over a seven-day period continuous observation. Most frequently observed were behaviours involving noncompliance with the treatment programme, and conflicts with the medical staff. Based upon an analysis of nine classes of behaviour included in the ISDB Scale, three groups of patients emerged with distinct patterns of indirect self-destructive activity: two consisting largely of noncompliant acting-out behaviours, and one involving more direct forms of self-injury.