This paper presents a tool for extracting multi-word expressions from corpora in Modern Greek, which is used together with a parallel concordancer to augment the lexicon of a rule-based machine-translation system. The tool is part of a larger extraction system that relies, in turn, on a multilingual parser developed over the past decade in our laboratory. The paper reviews the various NLP modules and resources which enable the retrieval of Greek multi-word expressions and their translations: the Greek parser, its lexical database, the extraction and concordancing system.