Recent development in OPAC systems have made search and retrieval of library catalogs anywhere, anytime possible. However, due to the discrepancies among different systems, users have to face different interfaces and usage. Furthermore, searching among several OPAC systems requires serial connection to one after another. To overcome this problem, this article discusses an implementation of an OPAC system based on the WWW and Z39.50 protocols. The implemented OPAC system allow multi-database search and natural language-like queries, thus reducing the tedious work and difficulties in query formulation. Possible problems encountered in developing such a system are discussed. It is hoped that the implementation experiences will help other libraries in establishing a similar Z39.50 service.