Electronic lexical resources almost never contain etymological information. The availability of such information, if properly formalised, could open up the possibility of developing automatic tools targeted towards historical and comparative linguistics, as well as significantly improving the automatic processing of ancient languages. We describe here the process we implemented for extracting etymological data from the etymological notices found in Wiktionary. We have produced a multilingual database of nearly one million lexemes and a database of more than half a million etymological relations between lexemes.