Abstract. As software systems become bigger and more complex, software developers need to cope with a growing amount of information and knowledge. The knowledge generated during the software development process can be a valuable asset for a software company. But in order to take advantage of this knowledge, the company must store and manage it for reuse. Ontologies are a powerful mechanism for representing knowledge and encoding its meaning. These structures can be used to model and represent the knowledge, stored in a knowledge management system, and classify it according to the knowledge domain that the system supports. This paper describes the Semantic Reuse System (SRS), which takes advantage of ontologies, represented using the knowledge representation languages of the Semantic Web, for software development knowledge reuse. We describe how this knowledge is stored and the reasoning mechanisms that support the reuse. Key words: Ontologies, Sematic Web, Software Reuse, Knowledge Man...