This paper presents the "CL/TB" programming interface for Allegro CL (an implementation of Common Lisp.) and the relational database management system TransBase. The interface and its components are presently running on SUN UNIX workstations but can easily be installed on all major UNIX workstations. CL/TB supports data manipulation, data definition, and data control. The database system is called by sending SQL-statements as strings from Allegro CL. Basically, CL/TB offers the prominent services of the underlying TransBase programming interface (TBX). The services are successfully integrated into the functional environment of Lisp and enhanced by many additional features to improve ease of use, programming security, and error support. Thus operating on a database system via CL/TB is easy even for unexperienced users. Furthermore CL/TB is compatible with the relational algebra R-Lisp.Structure, design, implementation, and performance data axe presented and its application is illustrated by examples.