The core of the health information system in the hospitals lies in the medical records, which contain all the data concerning diseases and practices. Then questions arise whether the medical records contain all the data needed in the reliable, complete and timely manners while meeting standards for confidentiality. In this study, we reviewed medical records of 11 general tertiary care hospitals in Seoul, Korea, according to the criteria we made based on the JCAHO's hospital accreditation manual. The focus of review was whether the medical records contain the valuable information fully and in timely manners. But the result was no better than our expectations. More caution should be given for the EPR software engineers to catch up all the information needed from the medical records. We also examine the cause of variation among hospitals and want to give basic information concerning the medical records for implementing the standardized EPR and suggest the method for keeping complete health information