During the last year many changes have been introduced into the system of maintaining OMIM. There are three major components of the reorganization. First, a distributed editorial system was introduced which provides a three-tiered editorial board with senior editors, science writers and subject editors. Second, MIM entries have been restructured to provide separate gene and phenotype information and to organize them into separate catalogs. The restructuring also establishes clearly defined sections for entering new information, converts old entries to the new structure, and establishes a file maintenance and editorial system in SGML format. Third, the entry numbering and naming system has been modified. In addition, the information has been made available through a variety of output media, including books, CD-ROM and online access based on the IRx, WAIS, Gopher and WWW formats.