Picture Archiving and Communications Systems are sophisticated computer systems designed to store and display medical images. It has been suggested that these systems may be more cost effective than film in practicing radiology because of better access to images by multiple users, better integration of information from multiple studies, and more rapid delivery of diagnostic reports to clinical physicians. Development of these systems is in its early stages and questions have arisen as to what functions an image management system should have and how it should interact with stand alone radiology information systems (RIS) and hospital information systems (HIS). Over the past decade, computer systems have undergone gradual reorganization from highly centralized hospital (or medical center) information systems toward decentralized departmental systems. The former systems often provided global functions but did not have the flexibility to meet the needs of individual departments. Some individual departmental systems were developed to meet specific requirements, but they were often unable to communicate with other systems within a medical center. Today many RIS's have the ability to provide departmental management tools, as well as to communicate with external systems. In order to achieve a filmless environment, PACS and HIS must be integrated with RIS systems to provide the level of information currently available. An additional goal of these systems is to automate operations and reduce the workload for technologists, admission personnel, file room staff, and radiologists.