This article describes the development of an expert system prototype to aid nursing diagnosis. The system is called CANDI, which stands for Computer-Aided Nursing Diagnosis and Intervention. Expert systems in nursing and medicine and selected decision-making models in nursing are reviewed and an overview of software and hardware used in the system is presented. At the time of this report, the development of the natural language user interface and an automated system for collecting patient data have been completed. The approach to the development of the knowledge base and inference engine are also discussed. By sharing this work, the authors' goal is to stimulate others to apply computer technology to nursing, to enhance the quality of nursing care, and to increase the efficiency by which selected nursing functions can be accomplished.