The course of expansion of spherical particle beds fluidized with Boger fluids, based on aqueous solutions of polyalkylene glycol Emkarox HV 45 with small addition of high molecular weight polyethylene oxide Polyox WSR Coagulant, was investigated in the creeping flow region. It was found that the expansion curve courses are different in comparison with those observed for Newtonian fluids. The non-linear shape of expansion curves indicates the transition of uniform fluidization state to an aggregative one due to the liquid elasticity. On the other hand, the influence of liquid elasticity on the course of fluidization manifests itself less intensively than in the case of fluidization with strongly shear thinning and elastic polymer solutions. In the latter case, the fluid shear thinning enhances the creation of inhomogeneities in the bed.