In this paper, artificial intelligence applications in library and information science are reviewed. Especially, natural language processing and expert systems are represented as the two major application areas. In natural language processing, natural language interface systems and .question-answering systems are discussed in detail with some specific examples. In the second part of the paper, online search intermidiary systems, reference expert systems, classification and cataloging expert systems are described as possible expert systems to be developed in libraries and information systems. As a conclusion, implications of the artificial intelligence applications for librarians and information scientists are suggested.