Every jurisdiction requires physicians to report certain types of injuries to law enforcement officials or protection agencies. Generally these laws require reporting of assaults, family violence, and criminal activity. The courts and codes of professional behavior have created a duty to report persons who are dangerous because of insanity. Physicians should avoid the tendency to investigate the crime before reporting it. Particularly in cases of family violence, the victim may have a plausible explanation of the injury and be anxious to avoid reporting. The injured person may fear reprisals or may be under investigation already. Proper reports should be made despite the victim’s wishes. It will be up to the law enforcement agency to determine what use will be made of the report.