CD-ROMs (Compact Disk - Read Only Memory), vvhich have been fre* quently discussed in the literatüre, are introduced in this paper. Some articles and the demonstratlon diskette of the Library Coorporation that was sent to the Library of Bilkent University have been made use of. The advantages (the high storage capacity of CD-ROMs, the elimination expenses durüıg online searching sessions) and disadvantages (the lack of standardize* tion, the lack of the facility of vvritinğ on CD-ROMs) of CD-ROMs are discussed. Several examples of databases vvhich vvere produced on CD-ROM have been given.