The microcomputer allows for the design of a system that functions integrally with both the day-to-day and long-term needs of a consultation-liaison psychiatric service. This article describes a microcomputer system and data structure that can accomplish many of the same research tasks as a minicomputer system. In addition, the same data item inputs can be used to develop management reports that can facilitate the administrative as well as the pedagogic needs of a consultation-liaison service. Because of the daily availability and review of output reports, supervisors' corrections are made that enhance the reliability of the data. The program format provides 1) an intake form with pertinent identifying demographic data; 2) an activity file that contains every encounter between the consultant and the patient as well as research, supervisory, and liaison activities (which permit cost-effectiveness analysis); 3) a master clinical data base containing 255 variables for each case seen; 4) a computer-generated chart note; 5) letters to referring physicians; 6) clinical activity descriptions for billing; and 7) a file for pertinent literature searches. Since certain analyses may be limited in the microsystem, its interactive capacity with mainframe computers allows for complex functions. The microsystem described presently emphasizes flexibility, accessibility, and step-by-step development of files as needed by a particular consultation-liaison service. Finally, microcomputers are available at a fraction of the cost of the minicomputer or mainframe systems.