Clinical guidelines and care maps are important tools for improving quality of care and reducing costs. However, problems of quantity, quality, and accessibility of data recorded in the inpatient medical record have not been solved by the implementation of clinical pathways. Variance or "charting by exception" improves legibility, in part. The aim of the present study was to design a computer-based medical record on a database platform to provide legible notes within a clinical guideline and variance charting framework.A computerized database program was written, integrating pre-established clinical guidelines into a user-friendly interface according to modification of the charting by exception principles. Patient care guidelines were provided for each postoperative day. After an initial debugging process by entering data from old charts of patients, the software was installed and its function was evaluated on selected patients. The charting time was compared with the standard charting method. Functionality and user friendliness were assessed.After a brief introduction of ten minutes, all users were able to use the software without difficulties. It was found to be functional and user friendly. The charting time was shorter for the computer-based inpatient medical record compared with the charting time of the standard charts. Because all daily notes were printed on standardized forms on a laser printer, legibility was excellent.The results of this pilot study suggest that the idea of computer-based inpatient medical record integrating an on-line inpatient medical record in a database platform is feasible. Further development and integration with other hospital information systems and the other health-care providers is required.