OWLDiff is a project aiming at providing diff/merge functionality for OWL ontologies. It can be used as a

The OWLDiff provides the following features:

OWLDiff paper:

Petr Kremen, Marek Smid and Zdenek Kouba. OWLDiff: A practical tool for comparison and merge of OWL ontologies. In Proceedings of DEXA 2011 Workshops. IEEE Computer Society Press. To appear in September 2011.

The project is available at SourceForge.