This work has been done for the subject taught by professor Ricardo Gómez (UPV-EHU), Euskal Lexikografia (Basque Lexicography). There, we have compared José Francisco Aizkibel's Euzkeratik Erderara Biurtzeko Itztegia's (Diccionario basco-español) manuscript and the edition published some years later by Eusebio López in 1883-84. We have done the description of the manuscript. Moreover, instead of demonstrating that López used the manuscript which is kept in Koldo Mitxelena Kulturunea, we have shown that he modified, added and corrected (or even made new mistakes) some things. Finally, we have given some data about the number of editions of the dictionnary and about the differences between them.