This paper discusses reference services in the digital library. The introduction provides definitions of a digital library, and the first section summarizes the purposes of a digital library system, as well as key roles for information professionals. The second section provides examples of mediated and unmediated digital reference. The third section addresses user expectations for reference in the digital environment. The fourth section presents results of focus groups conducted at the National Library of Australia to assess the needs of users both in the networked and print library environment; gaps in user and library perceptions are highlighted. The fifth section describes four models for digital reference: (1) the Collaborative Digital Reference Service, a pilot project developed by the Library of Congress to test the provision of professional library-quality reference service to users any time, anywhere; (2) the Co-operative Online Research Catalog (CORC), an OCLC project comprising a catalog of Internet resources and a mechanism to share pathfinders to help users identify Internet resources; (3) the Council of Australian State Libraries Working Group on Reference Issues, established to identify issues in which a collaborative approach will result in better reference services in Australian libraries; and (4) subject gateways. The final section considers future directions. (MES)