  Context: Determining the parameters of massive stars is crucial to understand
many processes in galaxies and the Universe, since these objects are important
sources of ionization, chemical enrichment and momentum. 10m class telescopes
enable us to perform detailed quantitative spectroscopic analyses of massive
stars in other galaxies, sampling areas of different metallicity. Relating the
stars to their environment is crucial to understand the physical processes
ruling their formation and evolution.
  Aims: In preparation for the GTC, our goal is to build a catalogue of massive
star candidates in the metal-poor irregular galaxy IC1613 with high astrometric
accuracy, apt for the current generation of multi-object spectrographs. A
census of OB associations in this galaxy is also needed, to provide important
additional information about age and environment of the candidate OB stars.
  Methods: From INT-WFC observations, we have built an astrometric and
photometric catalogue of stars in IC1613. Candidate blue massive stars are
preselected from their colors. A friends-of-friends algorithm is developed to
find their clustering in the galaxy. While a common physical origin for all the
members of the associations cannot be ensured, this is a necessary first step
to place candidate OB stars in a population context.
  Results: We have produced a deep catalogue of targets in IC1613 that covers a
large field of view. To achieve high astrometric accuracy a new astrometric
procedure is developed for the INT-WFC data. We have also built a catalogue of
OB associations in IC1613. We have found that they concentrate in the central
regions, specially in the HII bubbles. The study of extinction confirms that it
is patchy, with local values of color-excess above the foreground value.
