Measurement of the Gluon Polarization of the Nucleon at COMPASS

The determination of the gluon polarization $\Delta G/G$ represents one of the main goals of the COMPASS Collaboration at CERN. This quantity is experimentally accessible by selecting photon gluon fusion (PGF) events in the scattering of a polarized 160 GeV muon beam off a polarized $^{6}$LiD target. At COMPASS the PGF mechanism is tagged by means of three different channels: charmed meson production and high-$pT$ hadron pairs in either electro-production ($Q^{2} >$ 1 GeV$^{2}$) or quasi-real photo-production ($Q^{2} <$ 1 GeV$^{2}$). The status of the different analyses and the $\Delta G/G$ results obtained from the 2002-04 data samples are presented. The most precise measurement comes from the hight-$pT$ quasi-real photo-production, yielding a small gluon polarization.