Immunization (IZ) information systems (IISs) are confidential, computerized, population-based systems that collect and consolidate IZ data from vaccination providers. The American Academy of Pediatrics continues to support the development and implementation of IISs as a beneficial tool to provide quality health care for children. Since the last revision of the American Academy of Pediatrics policy statement on IISs in 2006, numerous public health events and new data demonstrate the importance and value of these systems in society and expand the functionality and benefits of IISs beyond the basic IZ database intended to improve childhood IZ rates. This policy statement update will describe additional functions and benefits of IISs, as well as persistent and novel challenges and barriers that these systems face and pose to practicing pediatricians. Pediatricians and other pediatric health care practitioners should be aware of the value of IISs to society, the incentives and barriers involved in incorporating IIS access into a medical practice, and the opportunities to improve IISs and their functionality and usability in daily pediatric practice.