The duty to report certain conditions to public health or law enforcement authorities is one that falls on all physicians and other health care workers as part of their duty to protect the public from harm. In an open society, others, such as teachers, clergy, police officers, or simply neighbors, share the responsibility of protecting individuals at risk, often by reporting them to authorities. The emergency physician and others in the emergency department are uniquely positioned to identify people at risk or who pose a risk, and to report them as required or allowed under the law. In some circumstances, these duties may conflict with ethical duties such as respect for patient autonomy or to protect confidentiality. This article will examine mandatory and permissive reporting laws in various states from an ethical perspective. It will also explore emerging issues such as the reporting of suspected human trafficking. Competing Interests: The authors have no conflicts of interest to report.