Studies of heavy quark bound states, like J/psi meson, provide a useful tool to investigate QCD properties. Many general features of J/psi production, such as cross-sections and transverse momentum distributions are well described by many existing models. In order to differentiate between various theoretical models one has to study J/psi production in more details. One of the observables which can be used for this purpose is angular distribution of leptons produced in quarkonium decays, usually called polarization or spin asymmetry.
The PHENIX experiment at RHIC has measured inclusive J/psi polar and azimuthal angular decay coefficients at the mid (|y|<0.35) and forward (1.2<|y|<2.2) rapidity in p+p collisions at 200 GeV and 510 GeV. In this talk the analysis details as well as the results in different polarization frames will be presented and compared to theory.