Evolutionary models predict low rotation rates for Wolf-Rayet (WR)
stars, as most of the angular momentum should be carried away by the
high mass-loss rates. On the other hand, the prediction that the
collapse of rapidly rotating massive stars (very likely WR stars) is
responsible for long Gamma-Ray Bursters, seems to point to relatively
fast rotation rates for at least some WR stars. Unfortunately, the
photosphere of WR stars is vieled by a hot and dense stellar wind and
cannot be observed directly. Hence, no rotation rate has been
determined yet for the WR stars.

However, the rotation period of WR stars can be deduced from periodic
spectroscopic large-scale variability, when present. This type of
variation is likely caused by perturbations at the base of the wind
resulting in density enhancements or deficiencies that are
subsequently carried away by the wind. Combined with the rotation of
the star, it generates spiral patterns called Co-rotating
Interaction Regions (CIRs). This wind density distribution translates
into large-scale periodic spectroscopic variations in the wind
emission lines.

A systematic search for large-scale spectroscopic variability in
single WR stars brighter than V~16 is currently carrying out using
(among others) the Gemini-South Poor Weather time. This survey will
allow us to characterize and to determine the type of line-profile
varaibility of WR stars by following the evolution of the shape of
different lines over several nights. Up to date, CIRs have been
detected in the wind of a dozen of WR stars and the rotation rate of 6
WR stars could have been determined yet.