  This paper describes work performed withing the CRATER ({\em C}orpus {\em
R}esources {\em A}nd {\em T}erminology {\em E}xt{\em R}action, MLAP-93/20)
project, funded by the Commission of the European Communities. In particular,
it addresses the issue of adapting the Xerox Tagger to Spanish in order to tag
the Spanish version of the ITU (International Telecommunications Union) corpus.
The model implemented by this tagger is briefly presented along with some
modifications performed on it in order to use some parameters not
probabilistically estimated. Initial decisions, like the tagset, the lexicon
and the training corpus are also discussed. Finally, results are presented and
the benefits of the {\em mixed model} justified.
