Phagocytic activity of monocyte and neutrophil leukocytes in rat blood was investigated C using monodisperse poly(glycidyl methacrylate) (poly(GMA)) microspheres. Interactions of monocyte and neutrophil leukocytes with plain poly(GMA), charged poly(GMA)-NH2 and biomodified poly(GMA) (poly(GMA)-albumin and opsonized poly(GMA)) was studied as a function of time. Here we report the cellular phagocytosis rate of particles and the total internalised particle amount. Phagocytes showed higher phagocytic activity for poly(GMA) microspheres carrying functional groups versus plain poly(GMA) particles. Phagocytic activity was the highest for opsonized poly(GMA) microspheres (P < 0.05).