The PHENIX experiment measured J/ψ production in pp, d+Au and Au+Au reactions at√SNN= 200 GeV over a wide range of rapidity and transverse momentum. The nuclear modification factor obtained by comparing the d+Au and pp cross sections as a function of rapidity, is consistent with shadowing of the gluon distribution functions. J/ψ production in Au+Au collisions was compared to the production in pp collisions and it was found to be inconsistent with models that predict strong enhancement relative to binary collision scaling.