Nucleon structure has been a major subject of study in the recent decades. Its composition in terms of quarks and gluons and how it depends on the momentum, position and spin has been one of the main fields of research of the COMPASS Collaboration. The COMPASS experiment is in operation at CERN since 2002 and presently approved to continue at least till 2021. During these years several different measurements were performed, among them the measurement of Semi Inclusive Deep Inelastic Scattering using longitudinal and transversely polarised NH3 and LiD targets and a high energy/intensity muon beam and the study of the Drell-Yan reaction using transversely polarised NH3 target and a negative pion beam. These measurements give us access to several parton distribution functions, the best known objects to describe the nucleon structure in momentum space. The main results on spin obtained by the COMPASS Collaboration in the last years will be presented.