Over the next few years, computer-stored medical records will become technically and economically feasible on a broad scale. Hybrid systems that include computer and traditional paper versions of the medical record and obtain their data from existing ancillary service systems will soon be widely available. Completely electronic medical records will follow. However, standards for exchanging clinical information between independent computers are needed to eliminate the reentry or interfacing costs otherwise required to obtain data from computerized ancillary services. Three kinds of benefits may be expected: (1) improved logistics and organization of the medical record to speed care and improve care givers' efficiency, (2) automatic computer review of the medical record to limit errors and control costs, and (3) systematic analysis of past clinical experience to guide future practices and policies.