Objectives. CDC WONDER, a comprehensive on-line public health information system of the Centers for Disease Control and Prevention (CDC), was developed to place timely, action-oriented information in the hands of public health professionals. Methods. A unified system was developed de novo to be used for and to evolve along with public health. All data are stored and updated on the CDC mainframe. Results. CDC WONDER provides menu-driven access to 24 databases with information on mortality, hospital discharges, cancer incidence, notifiable diseases, acquired immunodeficiency syndrome, the Morbidity and Mortality Weekly Report, etc.; each database has on-line documentation. Results can be tabulated and graphed, and there is full-text searching of textual databases. Non-CDC staff have access via telephone connection. From August 1991 through June 1992, system databases were accessed 10 698 times, and there were 842 users (mean of 97 new users per month). Conclusions. CDC WONDER has shown that it is possible to build a large, on-line database of scientific data for public health professionals. CDC WONDER provides a common foundation from which to build information-based public health plans and policy and could help strengthen the public health system.
