The MELVYL MEDLINE project resulted in the addition of a full five-year subset of MEDLINE to the University of California's (UC) MELVYL online union catalog. As one of the nation's largest MEDLINE end-user searching systems, MELVYL MEDLINE provides online bibliographic access to the biomedical journal literature for all UC personnel at over seventy library sites or by remote access. This paper summarizes the project's accomplishments, reports MELVYL MEDLINE use and its impact on library services, and provides insights for other end-user search systems. The project serves as a model for adding databases to the MELVYL catalog and demonstrates the potential for use by other disciplines of a specialized database when readily accessible. Evaluation results report high user satisfaction and high usage. However, many advanced searching features of the interface are little used by searchers. Effects on library services include marked increases in reference transactions and interlibrary loans, with significant declines in mediated search services. Future MELVYL MEDLINE enhancements include matching search retrievals to journal locations, linkage to an online document delivery system, and consideration of building a superset of databases by combining MELVYL MEDLINE with citations from another database in the MELVYL catalog.