A hitherto unreported clinical entity, namely fecal impaction following methadone ingestion simulating acute intestinal obstruction, is described. Five cases admitted to the Surgical Service of the Beth Israel Medical Center in New York City are discussed. The nature and pathogenesis of the obstruction are analyzed and a suggested method of managing these cases is presented. It is emphasized that with expansion and increasing acceptance of Methadone Maintenance Treatment Programs, the number of such cases will increase. It is thus important that physicians become aware of the existence of this syndrome since involvement in methadone maintenance may be a life-long commitment for persons involved, thus increasing the incidence of the complication. It is also imperative to avoid unnecessary, and possibly harmful surgical intervention in such cases.