Results from COMPASS

COMPASS has accumulated so far 3 years of data, using the 160 GeV polarized muon beam from CERN and a polarized deuterium target to study the spin structure of the nucleon. The most precise determination of the gluon polarization is obtained at $x_{g}=$ 0.085 and a QCD scale $\mu^{2} =$ 3 GeV$^{2}$, from the high $p_{T}$ hadron pair channel at Q$^{2} <$ 1 GeV$^{2}$; the value $\Delta G/G =$ 0.016 $\pm$ 0.058 $\pm$ 0.055 is compatible with zero. Two other determinations are also shown, one using data at Q$^{2} >$ 1, and the other, data from the production of charmed D$^{0}$ mesons. New data on the spin structure function $g_{1}$ and results from a NLO QCD global analysis are presented A measurement of the Collins asymmetry on deuterium, linked to the transversely polarized parton distributions, is shown. Finally, major upgrades of the spectrometer are launched in view of the 2006 run.