Decision support is an important area of medical informatics research. Computer-based decision-support tools facilitate diagnosis and the management of patients after a diagnosis has been established. Diagnostic decision-support tools, such as Meditel, Quick Medical Reference, DXplain, Iliad, and PEM-DXP are potentially useful "expert systems." Other management-support tools, such as systems that use clinical practice guidelines to create reminders and alerts, also have been developed and evaluated. We do the following: (1) to provide an overview of diagnostic and management decision-support systems; (2) explore the background of and motivation behind these systems; (3) survey the uses of decision-support technology in office-based and inpatient pediatric practices; and (4) discuss the virtues and problems associated with some of these tools, and current controversies and future goals for computer-based decision support.