Mandatory child abuse reporting laws have developed a particular detail in the United States, Canada, and Australia as a central part of the governments' strategy to detect cases of abuse and neglect at an early stage, protect children, and facilitate the provision of services to children and families. Legislatures in these three countries have given detailed attention to the development of these laws over several decades, and the laws of these jurisdictions continue to evolve in response to new phenomenon and evidence of successes and failures in child protection systems. However, the laws differ in significant ways, both within and between these nations, with the differences tending to broaden or narrow the scope of cases required to be reported. A comparison of key elements of these laws was conducted, disclosing significant differences and illuminating issues facing legislators and policymaking bodies and countries already having the law. Governments throughout the world are increasingly engaged with the challenge of detecting cases of maltreatment at an early stage, to protect children, and to facilitate the provision of services. Many nations have enacted legislation commonly known as mandatory reporting laws, requiring designated persons to report suspected abuse and neglect. The International Society for Prevention of Child Abuse and Neglect sought information from 161 countries about matters including the presence of legislative and policy based reporting duties. Of the 72 countries responding, 49 indicated the presence of such duties in law or policy, and 12 respondents indicated the presence of voluntary reporting by professionals. Some jurisdictions, like the United Kingdom and New Zealand, have chosen not to enact mandatory reporting laws for reasons including the perceived danger of over reporting of innocent cases, which is seen as adversely affecting the interests of children and families by diverting scarce resources from previously substantiated cases. Tables, references