Recent advances in research on phagocytosis include a better appreciation of the cross-talk between phagocytic receptors, the definition of multiple signaling domains within these receptors, and a deeper understanding of the downstream effector pathways leading to actin polymerization and particle internalization. Phagosome maturation in macrophages proceeds via a series of membrane fusion and fission events, which modify the phagosome in small increments, and appears to be regulated, in part, by GTP-binding proteins and perhaps by protein kinase C. The isolation of dysphagic mutants of Dictyostelium discoideum presages the identification of new genes required for phagocytosis.