The purpose of the work described in this article is to introduce UML use cases in a traditional development process of medium and small sized Information Systems. This work relies on the CASE tool Designer from the Oracle company and its associated development method CADM. This introduction has an impact on the development process used as well as on the tools notably in terms of coupling, transformation and traceability of the various models used. The three axis of this work are the following ones : • Adding a phase of requirements capture with the help of use cases prior to the CADM development method currently used with Designer. • Defining rules to draft the use cases as well as rules for the transformation and traceability towards Designer analysis and design models (function hierarchy, design modules). • Extending the CASE tool and quite especially its repository so that it integrates the management of use cases: general properties, traceability links between the various elements contained in the repository, versioning, etc.