The regulations of the Joint Commission on Accreditation of Hospitals stipulate that every emergency department must maintain a control register or logbook of patients seen. The retrieval of handwritten logbook data characteristically is a slow and tedious task that is prone to error. A computerized logbook has been developed for use on personal microcomputers using an economical database management system. Each patient record consists of 16 fields, including basic identifying data, chief complaint, diagnosis, physicians involved, and disposition. The daily log of patients seen is a computer-generated printout containing nearly four times the number of patients per printed page as our handwritten log system. It is now possible to obtain listings of admissions, mortalities, daily radiographs, laboratory cultures, and physicians patient lists 24 hours a day. The system is a valuable resource in an emergency medicine residency, and allows our program to generate interesting case and radiograph listings. Research data can be obtained in a fraction of the time and with a fraction of the effort usually required by manual methods.