Abstract. In recent years much research has been conducted on building Thesauri and enhancing them with new terms and relationships. I propose to build and evaluate a system for automatically updating the lexicon of Roget’s Thesaurus. Roget’s has been shown to lend itself well to many Natural Language Processing tasks. One of the factors limiting Roget’s use is that the only publicly available version of Roget’s is from 1911 and is sorely in need of an updated lexicon.