The only aspect of Old Basque dictionaries which seems to have attracted the attention of researchers has been their potential contribution to the lexical inventory of this language: this is an ahistorical endogenous and utilitarian approach. The method -or lack of it- which underlies this approach brings about serious errors. These errors not only invalidate the conclusions but they also frequentely misportray the only history which this research is concerned with: the history of Basque words.